Will a Common Size Freezer Hold a Frozen Pizza?

I don't think you're going to find a common size anything over all the makes and models of 'C's. But to give you an idea, I just drove to my building where I keep my 2005 Fleetwood MH. I have a Dometic refrigerator/freezer. The freezer compartment measures 17" wide by 13" high by 10 1/2" deep.
If freezer size is important to your buying decision, you may want to measure your favorite pizza and then measure the freezer compartment of the RVs that you're considering.