For Which of the Following Reasons Did President Harry Truman

For which of the following reasons did President Harry Truman authorize use of the atomic bomb in 1945?

A) Germany refused to surrender, even though the Soviets, British, and Americans were converging on Berlin.
B) Truman feared that if he did not use the bomb, the Russians would continue their drive to spread communism into western Europe.
C) The bomb had never been tested, and scientists needed to know if the theory behind it was valid.
D) An Allied invasion of Japan would cost hundreds of thousands of American lives, since the Japanese had vowed to defend the main islands to the last man, woman, and child.