The correct answer is A) support a Communist agenda for the US.
A politician accused of “McCarthyism” would most likely support a Communist agenda for the US.
We are referring to Wisconsin Republican Senator Joseph McCarthy who accused many that many members of the US federal government and the US military were supporting Communist activities in the mid-1950s. McCarthy just accused people but never offer a serious argument or proof, so he ended up being a liar and his political career ended.