A project has a discounted payback period that is equal to the required payback period. Given this, which of the following statements must be true?

a) the project's internal rate of return must equal the required return.

b) the project must have zero net present value

c) the project must have a profitability index that is equal to or greater than 1.0

d) the project will still be acceptable if the discount rate is increased

e) the project will not be acceptable under the payback rule