Evelyn Mastakis, CFA, is a quantitative analyst in a local securities firm and does research about the difference between ordinary annuity and annuitydue. If both have the same number of payments, payment amount, and frequency of payments and are discounted at the same positive rate, the present value of the ordinary annuity is:（）
A. greater than the present value of the annuity due.
B. less than the present value of the annuity due.
C. equal to the present value of the annuity due.