John F. Kennedy's strategy of flexible response a was an updated version of John Foster Dulles's doctrine of massive retaliation. b was used in his battle with the leadership of the steel industry. c called for a variety of military options that could be matched to the scope and importance of a crisis. d required increased spending on a variety of nuclear weapons systems to be deployed around the world. e cut back nuclear weapons in favor of guerrilla forces.

c called for a variety of military options that could be matched to the scope and importance of a crisis.

Explanation:

Flexible response was a strategy implemented by President Kennedy after he took office as a modern and more relevant response to the threat of Communism than the Eisenhower administration before him.

This new strategy called for using a variety of military options that would vary in scale based on the threat at hand. It also called for mutual deterrence which led to Kennedy and Khrushchev talking with each other a couple of times.