Answer:
The correct answer will be option-C
Explanation:
Intensity represents the amount of physical power that comes used by the body to perform an activity so the exercise intensity is the measure of the energy expended during an exercise which varies person to person.
The best method to measure the exercise intensity is the heartbeat or the pulse rate as the energy during exercise is represented by the consumption of oxygen in the cellular respiration.
So the oxygen consumption is a result of cardiovascular fitness or the working heart performs. The work performed by the heart can be only observed in the form of heartbeat for the pulse rate.
Thus, Option-C is the correct answer.
