Julia Minor (sister of Caesar)
Julia, also known as Julia Minor and Julia the Younger,( 101 – 51 BC) was the second of two daughters of Gaius Julius Caesar and Aurelia Cotta.
She was the sister of the dictator Gaius Julius Caesar, and the maternal grandmother of Augustus.
Julia the Younger
Julia the Younger (Classical Latin:) or Julilla (little Julia), Vipsania Julia Agrippina, Julia, Augustus' granddaughter, or Julia Minor (19 BC – c. AD 29), was a Roman noblewoman of the Julio-Claudian dynasty.
She was the first daughter and second child of Marcus Vipsanius Agrippa and Julia the Elder.
Along with her sister Agrippina
the Elder, Julia was raised and educated by her maternal grandfather Augustus and her maternal step-grandmother Livia Drusilla.
Julia the Younger was the elder granddaughter of the Emperor Augustus, stepdaughter of the Emperor Tiberius, maternal aunt of the Emperor Caligula and Empress Agrippina the Younger, second cousin of the Emperor Claudius, and maternal great-aunt of the Emperor Nero.
Scribonia (wife of Octavian)
Scribonia( c. 70 BC – c. 16 AD) was the second wife of Octavian, later the Roman Emperor Augustus, and the mother of his only natural child, Julia the Elder.
Through her youngest daughter she was the mother- in- law of the Emperor Tiberius, great- grandmother of the Emperor Caligula and Empress Agrippina the Younger, and great- great grandmother of the Emperor Nero.
Hannah Arnold
Hannah Arnold, also known as Hannah Waterman King, was the grandmother of Benedict Arnolds children.
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.
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.
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.
Julia the Elder
Julia the Elder (30 October 39 BC – AD 14), known to her contemporaries as Julia Caesaris filia or Julia Augusti filia
(Classical Latin: or), was the daughter of Augustus Caesar, the first Roman Emperor, and his second wife, Scribonia.
Julia was also stepsister and second wife of the Emperor Tiberius; maternal grandmother of the Emperor Caligula and the Empress Agrippina the Younger; grandmother-in-law of the Emperor Claudius; and maternal great-grandmother of the Emperor Nero.
Hubba bint Hulail
Hubba bint Hulail was the grandmother of Hashim ibn' Abd Manaf, thus the great- great- great- grandmother of the Islamic" Nabī"( Prophet) Muhammad ibn Abdullah.
Antonia Minor
Antonia Minor, also known as Julia Antonia Minor, Antonia the Younger or simply Antonia( 31 January 36 BC- 1 May AD 37) was the younger of two daughters of Mark Antony and Octavia Minor.
She was a niece of the Emperor Augustus, sister of Cleopatra Selene II, sister- in- law of the Emperor Tiberius, paternal grandmother of the Emperor Caligula and Empress Agrippina the Younger, mother of the Emperor Claudius, and both maternal great- grandmother and paternal great- aunt of the Emperor Nero.
She was additionally the maternal great- aunt of the Empress Valeria Messalina and Faustus Cornelius Sulla Felix, the paternal grandmother of Claudia Antonia, Claudia Octavia, and Britannicus and the maternal grandmother of Julia Livia and Tiberius Gemellus.

Question: Who is Julia The Younger's maternal grandmother?
Answer: Scribonia