The Answer is B: He wanted to prevent the advance of Communism. ;
Truman reacted strongly against North Korean because he wanted to prevent the advance of communism. At this time the United States was pursuing a policy of containment of communism and the Soviet Union around the world, and the U.S.' policy in Korea followed this.
President Truman reacted strongly to North Korea's attack on South Korea to prevent the advance of Communism, driven by the policy of containment. Fearing a domino effect of nations falling to Communism, he quickly ordered military support and sought United Nations assistance. His actions underscored a commitment to counter any aggression perceived to be backed by the Soviet Union.
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