According to the article, what did Plato and Aristotle have in common? Both lived in the Roman Republic. Both believed that philosopher-kings were the best leaders. Both thought that tyranny was a threat to government. Both thought that the rule of law was a threat to government.

C. Both thought that tyranny was a threat to the government.

Explanation:

Aristotle believed that the best form of government is where every man can live happily. Clearly, tyranny does not fulfill this belief, as tyranny involves all the power in the hands of a single person who becomes corrupt and selfish. Plato similarly believed that a tyrant lacks reason, and therefore the whole state lacks reason. He states that no outside governing power controls a tyrant's selfishness.

Incase you're doubtful, here's a photo.  

i believe their role is to instruct certain sections on when they are to join and when they are to stop