Question about Silhouettes

Let n be the surface normal in the OCS, p be the fragment position in the OCS, and e be the eye position in the WCS$.$ Let M be the object$-$to$-$world transform, and V be the world$-$to$-$view transform. All these vectors and matrices are homogeneous.

Which expression below is true when a fragment is exactly on a silhouette?

A$.($e $-$ Mp$)$n$=0$

B$.$Mp$$Mn$=0$

C$.$ V$($e$$p$)$Vn$=0$

D$.$ VMp$$VMn$=0$