In Order to Ensure That Experimental and Control Groups Are

In order to ensure that experimental and control groups are similar before the experiment begins,social scientists sometimes:

A) pair subjects who are identical on relevant variables and assign one to the control group and one to the experimental group.
B) create groups that are equivalent in terms of their averages on some relevant variables.
C) randomly assign subjects to the experimental and control groups.
D) match subjects on relevant variables.
E) engage in activities mentioned in all of these choices.