The correct answer is A. He took a strong stance against communist expansion.
Step-by-step explanation
According to the series of actions described in the statement, it can be affirmed that Kennedy was in a strong position against communism because he was monitoring the island of Cuba and that is why he discovered the missiles that were there. However, he did not allow himself to be intimidated by this threat, but rather he had a strong position against it, imposing a blockade on Cuba and demanding the withdrawal of the missiles. The only action he had to abort was the invasion of Cuba, however, he managed to get the missiles to be withdrawn and blockaded Cuba. Therefore, the correct answer is A. He took a strong stance against communist expansion.