question: What is the cause of death of Lady Sarah Chatto's mother?
context: [["Daniel Chatto", ["Daniel St George Chatto( born 22 April 1957), previously Daniel Chatto St George Sproule, is a British artist and former actor.", "He is the husband of Lady Sarah Chatto, the daughter of Princess Margaret, Countess of Snowdon, and niece of Queen Elizabeth II."]], ["Jane Fellowes, Baroness Fellowes", ["Cynthia Jane Fellowes, Baroness Fellowes( n\u00e9e Spencer; born 11 February 1957) is one of the two older sisters of Diana, Princess of Wales, the other being Lady Sarah McCorquodale."]], ["Lamman Rucker", ["Lamman Rucker( born October 6, 1971) is an American actor.", "Rucker began his career on the daytime soap operas\" As the World Turns\" and\" All My Children\", before roles in Tyler Perry's films", "\" Why Did I Get Married?", "Why Did I Get Married Too?\", and\" Meet the Browns\", and its television adaptation.", "In 2016, he began starring as Jacob Greenleaf in the Oprah Winfrey Network drama series,\" Greenleaf\"."]], ["Sarah Wilson (war correspondent)", ["Lady Sarah Wilson, RRC( 4 July 1865 \u2013 22 October 1929), born Lady Sarah Isabella Augusta Spencer- Churchill, became one of the first woman war correspondents in 1899, when she was recruited by Alfred Harmsworth to cover the Siege of Mafeking for the\" Daily Mail\" during the Second Boer War."]], ["Princess Margaret, Countess of Snowdon", ["Princess Margaret, Countess of Snowdon, (Margaret Rose Windsor; 21 August 1930 \u2013 9 February 2002) was the younger daughter of King George VI and Queen Elizabeth and the only sibling of Queen Elizabeth II.", "Margaret spent much of her childhood with her parents and sister.", "Her life changed dramatically in 1936, when her paternal uncle King Edward VIII abdicated to marry divorc\u00e9e Wallis Simpson.", "Margaret's father became king, and her sister became heir presumptive, with Margaret second in line to the throne.", "During the Second World War, the two sisters stayed at Windsor Castle despite suggestions to evacuate them to Canada.", "During the war years, Margaret was considered too young to perform any official duties and instead continued her education.", "After the war, Margaret fell in love with Group Captain Peter Townsend.", "In 1952, her father died, her sister became queen, and Townsend divorced his wife, Rosemary.", "He proposed to Margaret early the following year.", "Many in the government believed that he would be an unsuitable husband for the Queen's 22-year-old sister, and the Church of England refused to countenance marriage to a divorced man.", "Margaret eventually abandoned her plans with Townsend and married photographer Antony Armstrong-Jones in 1960; the Queen made him Earl of Snowdon.", "The couple had a son David and a daughter Sarah.", "Margaret was often viewed as a controversial member of the British royal family.", "Her divorce in 1978 received much negative publicity, and she was romantically associated with several men.", "Her health gradually deteriorated in the final two decades of her life.", "She was a heavy smoker for most of her adult life and had a lung operation in 1985, a bout of pneumonia in 1993, and at least three strokes between 1998 and 2001.", "She died at King Edward VII's Hospital in London after suffering a final stroke on 9 February 2002."]], ["Lady Sarah Lennox", ["Lady Sarah Lennox (14 February 1745 \u2013 August 1826) was the most notorious of the famous Lennox sisters, daughters of Charles Lennox, 2nd Duke of Richmond."]], ["Judith Madan", ["Judith Madan(\" n\u00e9e\" Cowper; 26 August 1702 \u2013 7 December 1781) was an English poet.", "She was the granddaughter of Lady Sarah Cowper( 1644 \u2013 1720), the diarist."]], ["Lady Sarah Chatto", ["Lady Sarah Frances Elizabeth Chatto (n\u00e9e Armstrong-Jones; born 1 May 1964) is a member of the extended British royal family.", "She is the only daughter of Princess Margaret, Countess of Snowdon, and Antony Armstrong-Jones, 1st Earl of Snowdon, and a niece of Queen Elizabeth II.", "At the time of her birth she was seventh in line of succession to the British throne and is currently 24th."]], ["Richard T. Jones", ["Richard Timothy Jones( born January 16, 1972) is an American actor.", "Jones is best known for his portrayals of Laveinio in the dramatic film\" The Wood\"( 1999) and Mike of the dramatic films\" Why Did I Get Married?\"( 2007) and\" Why Did I Get Married Too?\"( 2010).", "He is also well known for his role as Bruce Van Exel, court services officer on the CBS television series\" Judging Amy\" that aired from 1999 to 2005."]], ["Sarah Greville, Countess of Warwick", ["Sarah Greville, Countess of Warwick (4 February 1786 \u2013 30 January 1851), formerly Lady Sarah Elizabeth Greville and Lady Monson, was the wife of Henry Greville, 3rd Earl of Warwick.", "Lady Sarah was the daughter of John Savile, 2nd Earl of Mexborough in the Irish peerage, and his wife, the former Elizabeth Stephenson.", "The family home was at Methley Park, near Leeds.", "Her mother, the Countess of Mexborough, died in 1821.", "Lady Sarah's elder brother, John, known as Viscount Pollington, served as MP for Pontefract and became the 3rd Earl on the death of their father in 1830.", "On 30 October 1807, Lady Sarah married John George Monson, 4th Baron Monson of Burton, becoming Lady Monson.", "Her husband died in 1809, aged 24.", "They had one child, Frederick John Monson, 5th Baron Monson of Burton, who married Theodosia Blacker in 1832 but died childless in 1841.", "On 21 October 1816, Lady Monson remarried, at St. James's, Westminster, becoming Countess of Warwick.", "They had one son, George Greville (1818-1893), known during his father's lifetime as Lord Brooke.", "After the death of her elder son, Lord Monson, the countess continued to use his seat at Gatton Park as an occasional home.", "She was considered a notable philanthropist, her obituary saying:\"The life of this estimable lady was spent in one undiminishing and unceasing course of charity, kindness and benevolence; which was equally felt in the neighbourhood of Warwick Castle, and in the vicinity of her son Lord Monson's mansion at Gatton.\"", "She died in January 1851, at Clifton Gardens in London, aged 64, and was buried in St Andrew's churchyard at Gatton.", "Her husband survived her by two years, dying in August 1853, aged 74.", "He was succeeded in the earldom by their son."]]]
supporting_facts: [["Lady Sarah Chatto", 1], ["Princess Margaret, Countess of Snowdon", 15]]
evidences: [["Lady Sarah Frances Elizabeth Chatto", "mother", "Princess Margaret"], ["Princess Margaret", "cause of death", "stroke"]]
answer: stroke