question: Who is David Of Trebizond's paternal grandmother?
context: [["Mona Hopton Bell", ["Mona Hopton Bell( 1867- 1940) was a British artist, best known for her portraits of civic figures.", "She was the grandmother of the painter Jean H. Bell."]], ["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."]], ["David of Trebizond", ["David Megas Komnenos (\u2013 1 November 1463) was the last Emperor of Trebizond from 1459 to 1461.", "He was the third son of Emperor Alexios IV of Trebizond and Theodora Kantakouzene.", "Following the fall of Trebizond to the Ottoman Empire, he was taken captive with his family to the Ottoman capital, Constantinople, where he and his sons and nephew were executed in 1463.", "In July 2013, David and his sons and nephew were canonized by the Holy Synod of the Patriarchate of Constantinople.", "Their feast day was determined as 1 November, the anniversary of their deaths."]], ["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."]], ["Irene of Trebizond", ["Irene of Trebizond( died around 1382) was the bigamous wife of Basil of Trebizond, by whom he had two sons, Alexios and John( later Alexios III of Trebizond), and possibly three daughters Anna, Maria and Theodora."]], ["Helena Kantakouzene, Empress of Trebizond", ["Helena Kantakouzene( died 1463) was the second wife of David of Trebizond, the last Emperor of Trebizond.", "Recent research has led to doubts regarding her existence."]], ["Rusudan of Georgia, Empress of Trebizond", ["Rusudan of Georgia, Empress of Trebizond was a consort of Manuel I of Trebizond, and the mother of Empress Theodora.", "Very little is known for certain about her."]], ["Hannah Arnold", ["Hannah Arnold, also known as Hannah Waterman King, was the grandmother of Benedict Arnolds children."]], ["Alexios IV of Trebizond", ["Alexios IV Megas Komnenos or Alexius IV (1382\u20131429), Emperor of Trebizond from 5 March 1417 to October 1429.", "He was the son of Emperor Manuel III and Gulkhan-Eudokia of Georgia."]], ["Maria of Gothia", ["Maria of Gothia was the first wife of David of Trebizond, last Emperor of Trebizond, whom she married in 1426."]]]
supporting_facts: [["David of Trebizond", 1], ["Alexios IV of Trebizond", 1]]
evidences: [["David of Trebizond", "father", "Alexios IV of Trebizond"], ["Alexios IV of Trebizond", "mother", "Gulkhan-Eudokia of Georgia"]]
answer: Gulkhan-Eudokia of Georgia