$4.$ Which of the following statements is the most correct?

a$.$ In a financing$-$type project, if the IRR is lower than the cost of capital, then the project's NPV is positive

b$.$ If project A has a higher IRR than project B$,$ then project A must also have a higher NPV

c$.$ The IRR calculation implicitly assumes that all cash flows are reinvested at the rate that

equals the cost of capital of the project

d$.$ a and c are both correct