Which of the following is the key difference between the u. s. system of government and the communist system of government?
a. popular vote
b. multiple political parties
c. election of a president
d. campaign financing

The key difference between the American system of government, as well as every other democratic system, and the communist system is multi-party. Namely, in the communist system there is only one party, known as one-sided. After the establishment of communist regimes in the USSR as well as in the Eastern states, initially there were parties of various orientations, whose leaders quickly, "mysteriously" disappeared, emigrated, etc. In the communist systems, there is funding for the campaign, and the election for the president, but the choice of candidates is from only one party, which often all, apart from the "main", give up the candidacy, because they want to "contribute" to the strengthening of communism under one undisputed leader.

The answer is: B.