In ATM, Well Known VCIs are:

A.
6 for Signaling, 10 for ILMI and 18 for PNNI

B.
18 for Signaling, 5 for ILMI and 16 for PNNI

C.
5 for Signaling, 16 for ILMI and 18 for PNNI

D.
6 for Signaling, 18 for ILMI and 16 for PNNI

E.
there are no Well Known VCIs