Answer:
Millions of years ago, the Appalachians were taller than the Himalayas! Millions of years of erosion, however, have taken their toll. ... The crust that is now the Appalachians began folding over 300 million years ago, when the North American and African continental plates collided.
C is most likely your answer (my bad if I am wrong)
I think its because we don't know how to harness it, with out making things explode.
