Which of the following statements is CORRECT?

a$.$ If a project has "normal" cash flows, then it will have exactly two real IRRs.

b$.$ If a project has "normal" cash flows, then it can have only one real IRR, whereas a project with "nonnormal" cash flows might have more than one real IRR.

c$.$ If a project has "normal" cash flows, then its IRR must be positive.

d$.$ The definition of "normal" cash flows is that the cash flow stream has one or more negative cash flows followed by a stream of positive cash flows and then one negative cash flow at the end of the project's life.

e$.$ If a project has "normal" cash flows, then its MIRR must be positive. just give me the logic not the answer itself