Truman Decided to Drop the Atomic Bomb on the City

Truman decided to drop the atomic bomb on the city of Hiroshima and later Nagasaki because

A) he wanted to demonstrate the full force of the U.S. military.
B) Japan did not respond to an Allied ultimatum to end the war or face destruction.
C) he feared if he did not strike first, Japan would again launch an attack on U.S. soil, more devastating than Pearl Harbor.
D) he knew that the Japanese and German governments were developing a bomb of their own.
E) All of these choices.