Final answer:
Titus is not one of the Julio-Claudian Emperors. He belonged to the Flavian Dynasty, which succeeded the Julio-Claudian Dynasty.
Step-by-step explanation:
The emperor who is not one of the Julio-Claudian Emperors is A) Titus. The Julio-Claudian Emperors include Augustus, who was the first Roman emperor and reigned from 27 BCE to 14 CE; Tiberius (r. 14 – 37 CE), who was stepson to Augustus; Caligula (r. 37 – 41 CE), known as Gaius, who was the grandnephew and adopted son of Tiberius;
Claudius (r. 41 – 54 CE), the uncle of Caligula; and Nero (r. 54 – 68 CE), the last emperor of the Julio-Claudian dynasty and stepson to Claudius. On the other hand, Titus (r. 79 – 81 CE), along with his father Vespasian and brother Domitian, were part of the Flavian Dynasty, which followed after the Julio-Claudian Dynasty, with Vespasian becoming emperor after Nero's death.