Tom lives in the area affected by air pollution, so he has a breathing problem.

A. If John didn't live in the area affected by air pollution, he wouldn't have a breathing problem.

B. Tom will have a breathing problem if he lives in the area affected by air pollution.

C. If Tom lived in the area affected by air pollution, he would have a breathing problem.

D. Tom won't have a breathing problem if he doesn't live in the area affected by air pollution.