D. The United States would not attempt to invade Cuba.
Explanation:
The issue was raised during the Missile Crisis of 1962, the moment of the Cold War humanity came closest to nuclear war. The US discovered Soviet bases for nuclear missiles being installed in Cuba and president John F. Kennedy demanded their dismantling and withdrawal. He ordered a naval blockade of Cuba and put the armed forces on high alert. In secret negotiations with the Kremlin, Soviet top leader Nikita Khrushchev agreed to dismantle them and Kennedy gave the USSR a guarantee that the US would not invade Cuba.
