(A) American forces were too defeated for a land invasion.
(B) Japan’s geography would not allow a land invasion.
(C) ** A land invasion would result in too many American casualties.
(D) It was not possible to supply troops with weapons for a land invasion.
EXPLANATIONS BELOW
Concept note-1: -Truman stated that his decision to drop the bomb was purely military. A Normandy-type amphibious landing would have cost an estimated million casualties. Truman believed that the bombs saved Japanese lives as well. Prolonging the war was not an option for the President.
Concept note-2: -Other Choices In the years that followed, President Truman steadfastly defended his decision to use the atomic bombs. He argued that the bombings of Hiroshima and Nagasaki forced the Japanese to surrender quickly, thus avoiding an invasion that would have cost the lives of thousands of Americans.
Concept note-3: -Truman wanted to avoid an invasion of Japan. Truman hoped that the use of the bomb would and it’s astonishing effects would be enough for Japan to surrender and they would not have to invade them. The US dropped the bombs at Hiroshima and Nagasak.