MY SISTER IS OFTEN SICK BECAUSE SHE DOESN’T DO PHYSICAL EXERCISE....

My sister is often sick because she doesn’t do physical exercise.

A. If my sister does physical exercise, she won’t often be sick.

B. If my sister isn’t physical exercise, she does sick.

C. If my sister did physical exercise, she wouldn’t often be sick.

D. If my sister wasn’t physical exercise, she would do sick.