Final answer:
Colin Powell (option A) became the 2nd military leader of the State Department in 1981. He is a retired 4-star general who strongly opposed the decision to invade Iraq in 2003 and encouraged considering a course of action supported by the United Nations.
Step-by-step explanation:
The retired 4-star general who became the 2nd military leader of the State Department in 1981 was Colin Powell (option A). He is a well-respected general who served during Operation Desert Storm and was later appointed as Secretary of State by George W. Bush. Powell strongly opposed the decision to invade Iraq in 2003. He challenged other officials to produce clear objectives and strategies for the operation and encouraged considering a course of action if it had the support of the United Nations.