Which of the following is true of the real risk-free rate of interest? Most experts think that the real risk-free rate fluctuates in the range of 15 to 20 percent in the United States. Ob) It is easy to measure the real risk-free rate precisely. The real risk-free rate is the sum of nominal rate of interest and the average inflation rate. d) The real risk-free rate must include a component for the average inflation e) It is the rate of interest that would exist on default-free U.S. Treasury securities if no inflation were expected in the future