Which of these names did Octavian NOT hold before receiving the title Augustus in 27 BCE?

Explication

Augustus was the honorific title granted to him only in 27 BCE, so he did not carry that name beforehand. Gaius Octavius was his birth name, Gaius Julius Caesar Octavianus reflects his adoption by Caesar, and Octavian is the modern shorthand for that adopted name, all of which applied to him before 27 BCE.