$4.$ Which of the following statements is true? a$.$ We can use NPV to evaluate two mutually exclusive repeated projects b$.$ To make an investment decision based on IRR, we do not need to know the appropriate discount rate. c$.$ We can use profitability index to evaluate mutually exclusive project d$.$ For a given project, NPV and discounted payback period will reach the same decision if the targeted time is infinity. e$.$ When comparing two mutually exclusive projects using the IRR, we should always pick the one with a higher IRR.