What description matches the alternative exercise principle of specificity?

a. a workout program must progress in its level of difficulty in order
for the body to continue improving. if a workout program never
changes, the body will never reach a higher level of fitness.

b. alternating exercising different muscle groups is another way to
ensure full recovery of a given muscle or body part after a tough
workout.

c. exercise is most effective when a schedule is in place.
consistency keep you motivated and your body in motion.

d. targeted exercise should improve the performance of a certain
task. repetition of specific exercises will improve the givens
task.

{apex}