The correct answer is C) an Allied invasion of their homeland.
After the successful Allied invasion of the Philippines in late 1944, the Japanese were prepared for an Allied invasion of their homeland.
We are referring to "Operation Downfall."
And the final moments of World War II, the Allied forces of the United States, France, Great Britain, and Russia, were preparing an invasion of Japan with Operation Downfall. The operation was not necessary because Japan surrendered after the United States launched the atomic bombs in Hiroshima and Nagasaki.