In an Experiment, the Difference Between the Experimental Group and the Control

Multiple Choice

In an experiment, the difference between the experimental group and the control group is that

A) the experimental group is always larger than the control group.
B) the control group knows what is being tested in the experiment, but the experimental group is "blind" to the purpose of it.
C) the experimental group gets the special treatment that the researcher is studying and the control group doesn't.
D) the control group is always tested before the experimental group is.