Answer (B) is correct. The NPV method calculates the present values of estimated future net cash inflows and compares the total with the net cost of the investment. The cost of capital must be specified. If the NPV is positive, the project should be accepted. The IRR method computes the interest rate at which the NPV is zero. The IRR method is relatively easy to use when cash inflows are the same from one year to the next. However, when cash inflows differ from year to year, the IRR can be found only
through the use of trial and error. In such cases, the NPV method is usually easier to apply. Also, the NPV method can be used when the rate of return required for each year varies. For example, a company might want to achieve a higher rate of return in later years when risk might be greater. Only the NPV method can incorporate varying levels of rates of return.