question: Who is Frederick Of Luxembourg's paternal grandfather?
context: [["Beatrice of Luxembourg", ["Beatrice of Luxembourg( 1305 \u2013 11 November 1319), was by birth member of the House of Luxembourg and by marriage Queen of Hungary.", "She was the youngest child of Henry VII, Holy Roman Emperor and his wife, Margaret of Brabant.", "Her two siblings were John of Luxembourg and Marie of Luxembourg, Queen of France."]], ["Frederick of Luxembourg", ["Frederick of Luxembourg (965 \u2013 6 October 1019), Count of Moselgau, was a son of Siegfried of Luxembourg and Hedwig of Nordgau.", "By a wife whose name is unknown (certain historians give her as Ermentrude, Countess of Gleiberg), he had:"]], ["Frederick of Denmark (bishop)", ["Frederick of Denmark( 13 April 1532\u20137 October 1556) was the youngest son of Frederick I of Denmark and Sophie of Pomerania.", "He was the Prince- Bishop of Hildesheim and Bishop of Schleswig."]], ["Lyon Cohen", ["Lyon Cohen( 1868\u20131937) was a Polish- born Canadian businessman and a philanthropist.", "He was the grandfather of singer/ poet Leonard Cohen."]], ["Sigfried, Count of the Ardennes", ["Sigfried (or Siegfried) (\u2013 28 October 998) was count of the Ardennes and the first person to rule Luxembourg.", "He was an advocate of the abbeys of St. Maximin in Trier and Saint Willibrord in Echternach.", "He may have been the son of Count Palatine Wigeric of Lotharingia and Cunigunda.", "He was the founder of the House of Luxembourg, a branch of the House of Ardennes."]], ["Kaya Alp", ["Kaya Alp was, according to Ottoman tradition, the son of K\u0131z\u0131l Bu\u011fa and the father of Suleyman Shah, who was, in turn, the grandfather of Ertu\u011frul, and the great grandfather of the Ottoman Empire founder, Osman I."]], ["Abd al-Muttalib", ["Abd al- Muttalib Shaybah ibn Hashim( c. 497 \u2013 578) was the grandfather of Islamic prophet Muhammad."]], ["Imiza of Luxembourg", ["Imiza of Luxembourg( also Irmentrude and Ermentrude)( died after), was a German noblewoman.", "She was the daughter of Frederick of Luxembourg, and the wife of Welf II of Swabia."]], ["Duke Eugen of W\u00fcrttemberg (1758\u20131822)", ["Duke Eugen of W\u00fcrttemberg( 21 November 1758 \u2013 20 June 1822) was a German prince.", "He was the brother of Frederick I of W\u00fcrttemberg"]], ["Marie of Luxembourg, Queen of France", ["Marie of Luxembourg( 1304 \u2013 26 March 1324), was by birth member of the House of Luxembourg and by marriage Queen of France and Navarre.", "She was the daughter of Henry VII, Holy Roman Emperor and Margaret of Brabant.", "Her two siblings were John of Luxembourg and Beatrice of Luxembourg, Queen of Hungary."]]]
supporting_facts: [["Frederick of Luxembourg", 0], ["Sigfried, Count of the Ardennes", 2]]
evidences: [["Frederick of Luxembourg", "father", "Siegfried of Luxembourg"], ["Sigfried, Count of the Ardennes", "father", "Wigeric of Lotharingia"]]
answer: Wigeric of Lotharingia