During the Cold War, Cuba and the United States had a tense relationship. In 1962, the Soviet Union, a sponsor of Communist Cuba, installed nuclear missiles on the island. The United States, threatened by this aggression, blockaded Cuba. With the United States and the Soviet Union heavily armed with nuclear weapons, many people in both nations feared imminent nuclear war. After a tense two weeks, the Soviet Union agreed to remove the missiles in exchange for an American promise not to invade Cuba. Although the Cuban Missile Crisis was resolved peacefully, it serves as a powerful reminder of how close the Cold War came to becoming a very hot one indeed.
Which of the following is an effective summary of this paragraph?
A.) The Cuban Missile Crisis was caused by the Soviet Union installing missiles on Cuba.
B.) The Cuban Missile Crisis was unique among Cold War conflicts in how dangerous it was.
C.) The Soviet Union and the United States experienced a great deal of tension during the Cold War.
D.) The Cuban Missile Crisis showed how dangerous the Cold War was.

The answer is D.