Answer:
d. adjust it according to the type of exercise you are doing.
Step-by-step explanation:
When you train harder, your muscle fibers contract more vigorously, this factor generates more muscle fiber recruitment and also increases energy expenditure. Due to this intensity the exercise is interrupted because the muscle reaches fatigue quickly and the heart rate reaches near maximum level. Because of this, you need to adjust the intensity level of your workout to avoid getting hurt and having problems. This adjustment should be done according to the type of exercise you are doing.