At first read I thought that -A- was the center hole, which would make -C- redundant. The engineer told me that the hole doesn't actually mean anything, and that -A- is a plane, but it seems to me this would make -B- redundant.
I need some help from people who understand how PC-DMIS inspects profile. I don't want to start this program until I know I can make it work.

I am thinking that I may end up using two faces of the rectangle as primary/secondary, and the left face on the small end as tertiary. Any input?