The correct answer is A.
During the 1930's, America was displeased with Japan's aggressive attitude towards China. Since China was an ally, the US wanted to punish Japan for their behavior. This resulted in economic sanctions (punishments) and trade embargoes.
Along with this, once China was in World War II and facing off against Japan the US helped through the Lend-Lease program. This allowed the US to aid China with military weapons and technology.
Lastly, the US wanted to be closer to Japan in case of possible military action, hence why they had a base set up in Hawaii.