<span>An 1890 massacre left some 150 Native Americans dead, in what was the final clash between federal troops and the Sioux. In 1973, members of the American Indian Movement occupied Wounded Knee for 71 days to protest conditions on the reservation.</span>
Because he sees Japanese as disease from the outside but the communist is a disease from the inside and need to destroy before becoming an unstoppable force. Also the communist is a blocking of his plan to unify China in one flag to defeat the Japanese forces in the country.
A, because it explains a lot of the reason everything happened