I think the answer is B.
I haven’t taken the test, so please let me know if it’s correct or not. But based on reading the question and using what knowledge I have, I think it’s B.
The event that marked the end of the Roman Republic is often attributed to the defeat of Marc Antony in 31 BC at the Battle of Actium which ended the period of civil war.
Thomas Paine - The pamphlet of Common Sense.