Answer:
The correct answer would be C, Jannie should increase the intensity or length of her exercise programs because it is more difficult to maintain high fitness levels as you age.
Step-by-step explanation:
Jannie has been an active individual throughout her early childhood. Her fitness level was very high. Now she is moving forward in her age and if she wants to maintain this high level of fitness, then she should increase the level of exercise that she does, in order to stay fit and healthy, because when age increases, the stamina of a person decreases naturally, and if someone wants to maintain his or her level of high fitness, he should change himself and give more time to exercise or increase the level of intensity of the current exercise.