What are the cases in which the IRR and NPV might not give the same answer? In other words when is the IRR unreliable?

i$)$ Mutually Exclusive Projects

ii$)$ When the NPV is equal to $0$

iii$)$ Non$-$Normal Cash Flows

iv$)$ When the project involves aliens

a$)$ i and ii only

b$)$ ii and iv only

c$)$ i and iii only

d$)$ i$,$ ii$,$ and iii

e$)$ all of the above

$2$