Explanation: The reason why the answer is D is clearly because Less than two weeks after being sworn in as president, Harry S. Truman received a long report from Secretary of War Henry L. Stimson. “Within four months,” it began, “we shall in all probability have completed the most terrible weapon ever known in human history.” Truman’s decision to use the atomic bomb on Hiroshima and Nagasaki resulted from the interplay of his temperament and several other factors, including his perspective on the war objectives defined by his predecessor, Franklin D. Roosevelt, the expectations of the American public, an assessment of the possibilities of achieving a quick victory by other means, and the complex American relationship with the Soviet Union.
