Laura researched and designed a training program to help her increase her cardiovascular fitness. Unfortunately, after three months, she has still made no progress in her goals. What is the best thing for Laura to do next?

A. Give up on her program and find something new because it is not working
B. Immediately increase the duration of her workouts to see more progress
C. Evaluate and adjust her choice of activities, frequency, duration, and intensity
D. Significantly increase the intensity of her workouts to work her body much harder