Which of the following is (are) important in designing an experiment?

I.Control of all variables that might have an influence on the response variable.

II.Randomization of subjects to treatment groups.

III.Use of a large number of subjects to control for small-sample variability.

Select one:

a.

I only.

b.

II only.

c.

I and II only.

d.

II and III only.

e.

I, II, and III.