I would say who because it is calling for them in the context of who because they were just mentioned.
Answer:
Insubordination
Explanation:
General MacArthur did not suffer from a lack of ego. During the Korean War, he started to make decisions that ran counter to those of his commander in chief. So, Truman sacked him.
The answer is (c). worked for less money
I was formed as a form of defense against Germany.