Select from:
a). rivers.
b). force.
c). mildew.
d). wind.
e). magma.
f). Weight.
g). soda.
h). magnetism.
Given those answer options, answer the question: You are presented with the quiz "what affects rocks?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "rocks interacting with wind over long periods of time causes weathering" and "rocks weather at different rates". So, what's the best answer to the question?
A:
d).