I believe the answer is education.
The correct answer would be D, because
each of the other answer did cause some amount of conflict with the settlers and the Native Americans.
Hope this helped!!
The United States would continue to remain neutral is the answer. The doctrine basically said European colonization of the Americas should stop, and America should stop taking sides in European wars. Both should be distinct, basically.
Japan was able to recover so fast due to the Korean War. There was a huge surge of United Nation and United States troops that provided money and jobs. Japan was able to serve as a repair hub as well as a logistics base during that time.
