The United States believed that the economic aid provided by the Marshal Plan would help contain the spread of communism
I believe the answer is C.
The correct answer to this open question is the following.
The issues that encouraged membership in the Communist Party were poverty and racial discrimination, two of the most critical problems that affected the United States at the time.
When the Socialist Party of America ended in 1919, Communist people in the United States created the Communist Party on May 1, 1919, and permanently collaborated with the American Farmers organizations and many labor unions in the country. The platform of the Communist Party supported the end of racism in the United States and favored policies that helped the poor.
Nothing like that had ever been created before in history.
The Declaration of Independence states that when the govt abuses its power, the people have a right to change the government or even overthrow it.