Answer:
It had helped Britain become wealthier and all the other countries like France, Spain and Italy got excluded from international trade. Now those countries are doing fine, but Britain is "In the lead" of economy.
The American attitude shifted in favor of rights for Native Americans. This is based on "Polls showed that Americans believed in rights for Native Americans". Why it's not A is because it wasn't the polling that contributed to the act, but what the polls showed which is C.
To minimize the number of free and slave people in the United States states
