Answer: C
A prefix is added at the beginning of a word to change it's meaning.
Take the word "prefix" for example.
Pre- is the prefix of the word "prefix."
The answer is prefix.
Hope this helps!
Cassius: Jealous of Caesar and does not like him in any way fashion or form. He believes Caesar is not worthy of praise and is confused as to why an ordinary man like him can be lifted up and valued so greatly. He is manipulative, he is not honorable, he is strong-minded.
Brutus: Although he is swayed by Cassius's opinion and the people actions, he does have love for Caesar. He values his country over anthing. He is smart, conflicted, pensive and cautious.
The answer would be C, because him knowing that he can do this to his sister gives him knowledge which then causes him to have power over the situation.