What was the significance of the naval quarantine of Cuba?

Question

A.
If the United States did not remove its ships, then the Soviet Union would not remove its missiles from Cuba.

B.
If Soviets snuck past U.S. ships, then the two countries would be at war.

C.
If the United States snuck past Soviet ships, then the two countries would be at war.

D.
If the Soviet Union did not remove its ships, then the United States would not remove its missiles from Cuba.

Answer 1

A. If the United States did not remove its ships, then the Soviet Union would not remove its missiles from Cuba.