The correct options are
A USA
C Nepal
D India
China has a one-party system. In such a system, only one party gets to form the government again and again. Other parties are considered illegal and their members cannot get elected by the people. Hence, China is not a democracy.
In all the other countries given in the options - USA, Nepal and India - are democracies having two or more party systems. The members of these parties can be elected by the people in a democractic manner.