The Subject Matter of the Social Sciences Differs in What

The subject matter of the social sciences differs in what major respect from the subject matter of the physical sciences?

A) It involves human beings who belong to the same species (and possibly the same society) as the scientists themselves.
B) Social scientific facts are separate from social values.
C) Physical scientists can capture objective samples of reality, whereas social scientists cannot.
D) People cannot be studied; they can only be understood.