Why Is It Important to Divide by Df to Compute

Multiple Choice

Why is it important to divide by df to compute sample variance?

A) Doing so makes the sample variance an unbiased estimator of the population variance.
B) Doing so ensures that the value for sample variance varies between 0 and 1.
C) Doing so minimizes the likelihood that the sample variance will be a negative value.
D) It is not important; there is no advantage for dividing by df.