The correct answer is C. Real Discount Rate.
The real discount rate is the rate of return that investors expect to earn on an investment after adjusting for inflation. It is calculated by subtracting the inflation rate from the nominal interest rate.
The nominal interest rate is the interest rate that is actually paid on an investment. It is usually higher than the real interest rate because it includes an additional amount to compensate for inflation.
Inflation is the rate at which prices for goods and services are rising. It can erode the purchasing power of money, so it is important to account for it when calculating the present value of future cash flows.
The real discount rate is used to calculate the present value of future cash flows that are not expected to be affected by inflation. For example, the present value of a pension payment that is expected to be paid in 10 years would be calculated using the real discount rate.
The money discount rate is the rate of return that investors expect to earn on an investment without adjusting for inflation. It is calculated by adding the inflation rate to the nominal interest rate.
The risk free rate of interest is the rate of return that investors expect to earn on an investment that is considered to be very safe. It is usually lower than the nominal interest rate because it does not include an additional amount to compensate for risk.