Question: Who is Duke Georg Alexander Of Mecklenburg-Strelitz's maternal grandfather?

Knowledge 1: Duke Georg Alexander of Mecklenburg-Strelitz
Duke Georg Alexander of Mecklenburg-Strelitz (6 June 1859 – 5 December 1909) was the eldest of the two surviving sons of Duke Georg August of Mecklenburg-Strelitz and of Grand Duchess Catherine Mikhailovna of Russia.He was a great-grandson of Emperor Paul and a cousin of Emperor Alexander III of Russia.Although he was a German prince of the House of Mecklenburg-Strelitz, he was raised in Imperial Russia, where he lived all his life.He followed a career as an officer in the Russian army and was Major General, Commander of the Life Guard Dragoon Regiment.Georg Alexander was a music lover, a skillful cellist and composer.In 1896 he formed a private string quartet called the "Mecklenburg Quartet".He contracted a morganatic marriage and his rights and inheritance passed to his younger brother Charles Michael, Duke of Mecklenburg.His four children received the title of Counts of Carlow, but after Duke Georg Alexander's death, his unmarried brother adopted his son Georg, Count of Carlow, who became the heir to the House of Mecklenburg-Strelitz in 1934. [SEP] Knowledge 2: Grand Duchess Catherine Mikhailovna of Russia
Grand Duchess Catherine Mikhailovna of Russia  (28 August 1827 – 12 May 1894), was the third of five daughters of Grand Duke Michael Pavlovich of Russia (youngest son of EmperorPaul I and Princess Sophie Dorothea of Württemberg) and Princess Charlotte of Württemberg (eldest child of Prince Paul of Württemberg and Princess Charlotte of Saxe-Hildburghausen).
Knowledge 1: Duke Georg Alexander of Mecklenburg-Strelitz
Duke Georg Alexander of Mecklenburg-Strelitz (6 June 1859 – 5 December 1909) was the eldest of the two surviving sons of Duke Georg August of Mecklenburg-Strelitz and of Grand Duchess Catherine Mikhailovna of Russia.He was a great-grandson of Emperor Paul and a cousin of Emperor Alexander III of Russia.Although he was a German prince of the House of Mecklenburg-Strelitz, he was raised in Imperial Russia, where he lived all his life.He followed a career as an officer in the Russian army and was Major General, Commander of the Life Guard Dragoon Regiment.Georg Alexander was a music lover, a skillful cellist and composer.In 1896 he formed a private string quartet called the "Mecklenburg Quartet".He contracted a morganatic marriage and his rights and inheritance passed to his younger brother Charles Michael, Duke of Mecklenburg.His four children received the title of Counts of Carlow, but after Duke Georg Alexander's death, his unmarried brother adopted his son Georg, Count of Carlow, who became the heir to the House of Mecklenburg-Strelitz in 1934. [SEP] Knowledge 2: Duchess Helene of Mecklenburg-Strelitz
Duchess Helene of Mecklenburg-Strelitz (16 January 1857 – 28 August 1936) was a daughter of Duke Georg August of Mecklenburg-Strelitz and his wife, Grand Duchess Catherine Mikhailovna of Russia.She was the second wife of Prince Albert of Saxe-Altenburg.
Knowledge 1: Grand Duchess Catherine Mikhailovna of Russia
Grand Duchess Catherine Mikhailovna of Russia  (28 August 1827 – 12 May 1894), was the third of five daughters of Grand Duke Michael Pavlovich of Russia (youngest son of EmperorPaul I and Princess Sophie Dorothea of Württemberg) and Princess Charlotte of Württemberg (eldest child of Prince Paul of Württemberg and Princess Charlotte of Saxe-Hildburghausen). [SEP] Knowledge 2: Duchess Helene of Mecklenburg-Strelitz
Duchess Helene of Mecklenburg-Strelitz (16 January 1857 – 28 August 1936) was a daughter of Duke Georg August of Mecklenburg-Strelitz and his wife, Grand Duchess Catherine Mikhailovna of Russia.She was the second wife of Prince Albert of Saxe-Altenburg.

Answer: Grand Duke Michael Pavlovich of Russia