An analyst does research about the limitations of cash flow yield. Which of the following statements is least accurate to be a shortcoming in application of the cash flow yield measure（）
A. The projected cash flows are assumed to be reinvested at the cash flowyield.
B. The mortgage-backed or asset-backed security is assumed to be held until the final payoff of all the loans, based on some prepayment assumption.
C. Because of principle prepayments, in order to project cash flow it is necessary to make an assumption about the rate at which principle prepayments will occur.
