Which best describes the relationship between caesar and octavius

Julius Caesar was Octavius's maternal great uncle. Julius named Octavious as his heir to become the next caesar in his will after he was assassinated.

Octavius who later changed his name to Augustus was Julius Caesar's great nephew. He was close to his great uncle and brought up quickly through his young age. He was named in Julius' will to be his adopted son and heir after the assassination of Julius Caesar.