The correct answer is D) by insisting on minority rights.
American democracy balances the power of majority rule by insisting on minority rights.
The United States government pays attention to taking into consideration the necessities of minorities in America. If the concept of majority rules is not balanced, then everything is charged to one side creating an unbalance that is no good for any society, because the other side would have some kind of reaction that most of the times are through protest and rebellion. That is why under the majority rule it is very important to never displace the minorities.