Question: Who is Countess Alexandra Von Zarnekau's paternal grandmother?

Knowledge 1: Countess Alexandra von Zarnekau
Countess Alexandra Constantinovna von Zarnekau (Russian: графиня Александра Константиновна Зарнекау, 10 May 1883 - 28 May 1957) was the eldest daughter of Duke Constantine Petrovich of Oldenburg and his morganatic wife, Agrippina Japaridze, Countess von Zarnekau.At age 17, on 11 February 1900, Countess Alexandra married Prince George Alexandrovich Yuryevsky, the son of Tsar Alexander II by his mistress (and later wife), Ekaterina Mikhailovna Dolgorukova, the Princess Yourievskya.They were married at Nice, France, and had one child, Prince Alexander Georgievich Yourievsky, who was born 20 December 1901.Alexandra and George divorced in 1908.Countess Alexandra married secondly to Leo Vassilievich Narishkin on 17 October 1908 at Paris, France.During the First World War, Countess Alexandra worked as an administrator of the Russian hospital at Saloniki.After the war, she settled in Paris, France.She died there on 28 May 1957 at age 74. [SEP] Knowledge 2: Duke Constantine Petrovich of Oldenburg
Duke Constantine Frederick Peter of Oldenburg (tr. ; 9 May 1850 - 18 March 1906) was a son of Duke Peter Georgievich of Oldenburg and his wife Princess Therese of Nassau-Weilburg Known in the court of Tsar Nicholas II as Prince Constantine Petrovich Oldenburgsky, he was the father of the Russian Counts and Countesses von Zarnekau.
Knowledge 1: Countess Alexandra von Zarnekau
Countess Alexandra Constantinovna von Zarnekau (Russian: графиня Александра Константиновна Зарнекау, 10 May 1883 - 28 May 1957) was the eldest daughter of Duke Constantine Petrovich of Oldenburg and his morganatic wife, Agrippina Japaridze, Countess von Zarnekau.At age 17, on 11 February 1900, Countess Alexandra married Prince George Alexandrovich Yuryevsky, the son of Tsar Alexander II by his mistress (and later wife), Ekaterina Mikhailovna Dolgorukova, the Princess Yourievskya.They were married at Nice, France, and had one child, Prince Alexander Georgievich Yourievsky, who was born 20 December 1901.Alexandra and George divorced in 1908.Countess Alexandra married secondly to Leo Vassilievich Narishkin on 17 October 1908 at Paris, France.During the First World War, Countess Alexandra worked as an administrator of the Russian hospital at Saloniki.After the war, she settled in Paris, France.She died there on 28 May 1957 at age 74. [SEP] Knowledge 2: 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.
Knowledge 1: Countess Alexandra von Zarnekau
Countess Alexandra Constantinovna von Zarnekau (Russian: графиня Александра Константиновна Зарнекау, 10 May 1883 - 28 May 1957) was the eldest daughter of Duke Constantine Petrovich of Oldenburg and his morganatic wife, Agrippina Japaridze, Countess von Zarnekau.At age 17, on 11 February 1900, Countess Alexandra married Prince George Alexandrovich Yuryevsky, the son of Tsar Alexander II by his mistress (and later wife), Ekaterina Mikhailovna Dolgorukova, the Princess Yourievskya.They were married at Nice, France, and had one child, Prince Alexander Georgievich Yourievsky, who was born 20 December 1901.Alexandra and George divorced in 1908.Countess Alexandra married secondly to Leo Vassilievich Narishkin on 17 October 1908 at Paris, France.During the First World War, Countess Alexandra worked as an administrator of the Russian hospital at Saloniki.After the war, she settled in Paris, France.She died there on 28 May 1957 at age 74. [SEP] Knowledge 2: 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 CarlosI 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.

Answer: Princess Therese of Nassau-Weilburg