When a company controls an entire industry or a specific area of the economy it has a monopoly. Democratic governments tend to break up monopolies as they can be unhealthy for their economies. Monopolies can stifle innovation and competition.
Wanted to prevent future threats from Germany => Joseph Stalin
Wanted free elections in Eastern Europe => Winston Churchill
Wanted Soviet help against Japan => Franklin D. Roosevelt
The answer is C because as president they are taking an oath to uphold the laws stated in the Constitution.