question: Who is Margaretta Foster, 1St Viscountess Ferrard's paternal grandmother?
context: [["Hubba bint Hulail", ["Hubba bint Hulail was the grandmother of Hashim ibn' Abd Manaf, thus the great- great- great- grandmother of the Islamic\" Nab\u012b\"( Prophet) Muhammad ibn Abdullah."]], ["Tjuyu", ["Tjuyu( sometimes transliterated as Thuya or Thuyu) was an Egyptian noblewoman and the mother of queen Tiye, and the wife of Yuya.", "She is the grandmother of Akhenaten, and great grandmother of Tutankhamun."]], ["John Foster (Dunleer MP)", ["John Foster (1770 - April 1792), styled The Honourable, was an Anglo-Irish politician.", "Foster was the son of John Foster, 1st Baron Oriel and Margaretta, Viscountess Ferrard.", "He was educated at Eton College and Trinity College, Cambridge.", "Foster served as the Member of Parliament (MP) for Dunleer in the Irish House of Commons between 1790 and his early death in 1792.", "His brother Thomas Henry Foster succeeded him as MP."]], ["Margaretta Foster, 1st Viscountess Ferrard", ["Margaretta Amelia Foster, 1st Viscountess Ferrard (\"n\u00e9e\" Burgh; c. 1737 \u2013 20 January 1824) was an Anglo-Irish peeress.", "She was the daughter of Thomas Burgh and Anne Downes, daughter of Dive Downes, Bishop of Cork and Ross and his fourth wife Lady Catherine Fitzgerald.", "On 14 December 1764, she married the politician John Foster.", "On 5 June 1790, she was raised to the Peerage of Ireland as Baroness Oriel in her own right.", "The title was created in honour of her husband, but in such a way that would enable him to continue to serve as Speaker of the Irish House of Commons.", "On 22 November 1797, she was further honoured when she was made Viscountess Ferrard.", "Her husband was created Baron Oriel in his own right in 1821.", "Viscountess Ferrard had three children.", "She was succeeded in her titles by her eldest surviving son by John Foster, Thomas, who also succeeded to his father's barony on his death in 1828."]], ["Diana Guardato", ["Diana Guardato was a member of the aristocratic Patrician Guardato family, and had three children with King Ferdinand I: Diana Guardato is the 16th- Great Grandmother of His Royal Highness Albert II of Belgium, 15th- Great Grandmother of His Majesty Juan Carlos", "I of Spain, 17th- Great Grandmother of Philippe of Belgium, 14th- Great Grandmother of His Majesty Manuel II of Portugal, 16th- Great Grandmother of Grand Duke Henri, as well as many others."]], ["Dive Downes", ["Dive Downes( b Thornby, Northamptonshire 1652 \u2013 d Dublin 1709) was Bishop of Cork and Ross from 1699 to 1709.", "Downes was born in Northamptonshire, son of the Reverend Lewis Downes.", "He was educated at Trinity College, Dublin.", "He was ordained in 1678.", "In 1683 he became a prebendary of St Patrick's Cathedral, Dublin and in 1690 Archdeacon of Dublin.", "He was married four times.", "He married firstly Sarah Dodwell, dughter of Henry Dodwell of Athlone, secondly Anne Carleton, and thirdly Elizabeth Beecher, daughter of Thomas Beecher of Sherkin and widow of Horatio Townshend, by whom he had a daughter Elizabeth, who married her cousin Henry Baldwin of Mount Pleasant.", "By his fourth wife Catherine FitzGerald, daughter of the Honorable Robert FitzGerald and Mary Clotworthy, and sister of Robert FitzGerald, 19th Earl of Kildare, he had a son Robert Downes, MP for Kildare, of Donnybrook Castle, and a daughter Anne.", "Robert was the father of William Downes, 1st Baron Downes, Lord Chief Justice of Ireland.", "Anne married Thomas Burgh and was the mother of Margaretta Foster, 1st Viscountess Ferrard, and grandmother of Ulysses Burgh, 2nd Baron Downes.", "He was a conscientious bishop, and in 1699- 1700 he visited every parish in his diocese: his\" Visitation of Cork\" has survived."]], ["Anne Denman", ["Anne Denman( 1587\u20131661) was born in Olde Hall, Retford, Nottinghamshire.", "Through a fortunate second marriage with Thomas Aylesbury, she became the grandmother of Lady Anne Hyde, Duchess of York and great- grandmother of Queen Mary II and Queen Anne."]], ["Thomas Burgh (Lanesborough MP)", ["Thomas Burgh (1696 \u2013 20 September 1758) was an Anglo-Irish politician.", "He was the son of William Burgh and Margaret Parnell.", "Burgh sat in the Irish House of Commons as the Member of Parliament for Lanesborough between 1727 and his death in 1758.", "Burgh married Anne Downes, daughter of Rt.", "Rev. Dive Downes, Bishop of Cork and Ross and his fourth wife Lady Catherine Fitzgerald, sister of the Earl of Kildare, in 1731.", "They had eight children, three sons and five daughters.", "One of their daughters, Margaretta Burgh, married John Foster, 1st Baron Oriel and was created Viscountess Ferrard in 1797.", "One of his sons, also called Thomas, was the father of Ulysses Burgh, 2nd Baron Downes, who inherited the title by special remainder from his cousin William Downes, 1st Baron Downes, Lord Chief Justice of Ireland, a nephew of Anne Downes."]], ["Kaoru Hatoyama", ["After the elections of 2009, she became more widely known as the grandmother of Prime Minister Yukio Hatoyama and his politician brother Kunio Hatoyama."]], ["Hannah Arnold", ["Hannah Arnold, also known as Hannah Waterman King, was the grandmother of Benedict Arnolds children."]]]
supporting_facts: [["Margaretta Foster, 1st Viscountess Ferrard", 1], ["Thomas Burgh (Lanesborough MP)", 1]]
evidences: [["Margaretta Amelia Foster, 1st Viscountess Ferrard", "father", "Thomas Burgh"], ["Thomas Burgh", "mother", "Margaret Parnell"]]
answer: Margaret Parnell