What Is a Plausible Reason That Truman Authorized the Use

What is a plausible reason that Truman authorized the use of the atomic bomb against Japan?

A) to intimidate Stalin and ensure postwar American dominance
B) to warn Germany that it, too, would face atomic attack if it did not surrender
C) to kill as many Japanese as possible, in order to punish them for war crimes
D) to justify massive military expenditures on the Manhattan Project