Which of the following statements is (are) true concerning the time value of a single sum? 1. The higher the discount rate, the higher the present value. II. The longer the time period, the higher the future value. III. The larger the future value, the larger the present value. IV. The higher the discount rate, the higher the future value. OIV only III and IV only OI, II, and III only I and IV only II, III, and IV