Answer:
B. Brisk walking for thirty minutes three times a week
Explanation:
A person who is planning on participating a fitness program should start with a moderate-intensity exercise, just like "brisk walking." Vigorous aerobic dance, running and swimming are high-intensity exercises because they use the body's large muscle groups. They are not meant for starting a fitness program especially when they are done at longer periods of time. Exercise should be started at a slow pace while advancing it over time in order to accommodate one's level of stamina.