Stretching involves tightening a muscle as hard as possible, and then performing a static stretch of the same muscle.
a. ballistic
b. dynamic
c. static
d. pnf

B. Dynamic

Dynamic stretching involves tightening a muscle as hard as possible, and then performing a static stretch of the same muscle.

Explanation:

Dynamic stretching use movement and muscular effort to bring about a stretch. It takes soft tissues to their full length instead of holding it. After few seconds, the muscle that is stretched contracts and the muscles and tendons exert a force in the lengthened position. Dynamic stretching exercises improve performance if it is done before an activity that requires a lot of power.