Which One of the Following Represents a Critical Difference Between

Multiple Choice

Which one of the following represents a critical difference between the non-experimental and experimental methods?

A) Non-experimental methods involve operational definitions while experimental methods do not.
B) Experimental methods involve operational definitions while non-experimental methods do not.
C) Non-experimental methods involve the manipulation of variables while experimental methods do not.
D) Experimental methods involve the manipulation of variables while non-experimental methods do not.