Are you done with this?

Imagine this....

You are in a French Restaurant, just finished your main course of seafood risotto. What is left on the plate is the clam shells and prawn shells. You put your utensils together on the side to show that you are done with the meal. A ever attentive waiter approaches your table, look at you and ask "Are you done with this?"

I was so tempted to reply the following but was indecisive...

A. "Am I supposed to finish the clam shells too?"
B. "No...not really...let me chew down the clam shells too..."
C. "What do you think?"

Seriously, I don't mean to be sarcastic (or was I)...but there is NOTHING left on the plate besides uneatable things. I know that they are just trying to be polite to ask before clearing the plates but why can't they ask "May I clear this for you?" See! Doesn't this makes much more sense? I wonder how would the waiter react if I reply with response A.