Final answer:
After Augustus, who ruled until 14 CE, more than six emperors ruled, including those from the Julian Dynasty, the Flavian Dynasty, and the "Five Good Emperors", making the correct answer not listed among the options provided.
Step-by-step explanation:
The question asks how many emperors ruled after Caesar Augustus. According to the provided timeline and historical context, after Augustus, the Julian Dynasty included Tiberius (r. 14-37 CE), who was followed by several emperors until the last emperor of the Julian Dynasty who was Nero (r. 54-68 CE). The next dynasty, the Flavian Dynasty, started with Vespasian (r. 69-79 CE) and included his sons Titus (r. 79-81 CE) and Domitian (r. 81-96 CE). After the Flavian Dynasty, the period known as the rule of the "Five Good Emperors" lasted until the year 180 CE, highlighting the reign of a series of rulers who chose their successors based on merit rather than heredity.
By considering that Augustus ruled until 14 CE and the timeline provided, we include Tiberius, Caligula, Claudius, and Nero from the Julian Dynasty; then Vespasian, Titus, and Domitian from the Flavian Dynasty. Following that, the "Five Good Emperors" are Nerva, Trajan, Hadrian, Antoninus Pius, and Marcus Aurelius. So, more than six emperors ruled after Caesar Augustus, which makes the answer not listed among the given options (a) 3, (b) 4, (c) 5, or (d) 6).