Well it isn't D. Germany was on the ropes. It was all but over when the idea of the atomic bomb came up.
A: revenge was never a reason, although you might think it was.
B: His main fear was that after he had seen how hard the Japanese fought in Okinawa, he knew that the battle for Japan would be even worse: Japan had an army on the mainland that was 10 times that of Okinawa and they too would fight to the end. Answer B was a real concern.
C: He had no such agreement with the Soviet Union. In fact, a very small part of his reason for using the bomb was to warn the Soviets not to get any ideas about challenging the United States.