Which of the following statement is true?

I. A statistic describes the characteristic of a population.

II. If we triple the sample size, then the standard deviation of the sampling distribution of the sample mean will decrease by a factor of1/sqrt(3)

III. The standard deviation of a t-distribution becomes larger as we decrease the degrees of freedom.

A. I, II, and III

B. II and III

C. II only

D. I only

E. III only