Which of the Following Statements About Discount Rates Is False

Which of the following statements about discount rates is false?

A) A discount rate for computing NPV cannot change from one period to the next.
B) The discount rate for a risky investment should be higher than the discount rate for a risk-free investment.
C) Discount rates can be applied either to the cash flow from a transaction or the taxable income from a transaction.
D) Both a discount rate for computing NPV cannot change from one period to the next and discount rates can be applied either to the cash flow from a transaction or the taxable income from a transaction.