Without giving us the passage you have in front of you, maybe you can figure it out on your own (or perhaps already did). Which of the themes is evident in the passage you're looking at?
The rise of McCarthyism: Senator Joseph McCarthy led a vigorous campaign to root out all persons that had any suspicion of being communist sympathizers.
The elimination of the House Un-American Activities Committee: That was part of the backlash against McCarthyism, seeing that McCarthy and others had gone to far in their anti-communism crusade.
Opposition to Republicans supporting the Korean War: Though Truman's actions to get involve the United States in the war in Korean were initially popular, that popularity began to dwindle once China entered into the conflict and it became apparent this was going to be a protracted and difficult struggle.
The Truman Doctrine was first stated by the president to Congress in 1947, saying: "I<span>t must be the policy of the United States to support free people who are resisting attempted subjugation by armed minorities or by outside pressures." Essentially, the Truman Doctrine pledged American effort elsewhere in the world to check the spread of communist and Soviet influence. The policy was first put into action in 1948 by providing economic support to Greece and Turkey to stave off communist movement in those countries.</span>
The answer is B, a state can make laws that regulate commerce in neighboring states.
It would be John C Fremont. However he didn't win the whole election, the Democrat he was running against did.
