AP Bio Packet question. Please help!!?

Question

Why do the tropics & windward side of mountains recieve more rainfall than areas around 30 degree latitude or leward side of mountains?

a. rising air expands, cools, and drops its moisture.

b. descending air condenses and drops its moisture

c. the tropics and the windward side of mountains are closer to the ocean.

d. There is more solar radiation in the tropics and on the windward side of mountains.

e. the rotation of the earth determines global wind patterns

Answer 1

b