D. He Wanted to Save Lives
He was warned by his advisors that if he were to try an invade japan it would lengthen the war and cost the lives of many U.S. Troops
The native population of the Spanish colonies (i.e., Native Americans in the area) died off due to wars between Spanish settlers and natives, poor working conditions in enslavement, and the tons of diseases brought over by the Spanish that Native Americans' bodies did not know how to fight all drastically wiped out native Spanish populations. They had to bring in a lot of slaves from Africa to make up for these losses.
