Good luck finding a useable one. "B" does not equal "C" here. Yeah, they may look the same, but the quarter dimensions are not close! The location of the drain hole is irrelevant.
You'll be better off finding a good sheetmetal guy and have him fab one up for you, as I guarantee if you try to use that "B"-body part, you're going to have more work in that in trying to make that piece fit that hole, than if you simply have one made from scratch.