"Let me see your birth certificate".
or
A cow walking backwards
or
The question is irrelevant, since you couldn't find the dolls even if you knew how many. (Note: Well, this was a good joke in 1983-84. . . .)
or
I'll meet you at the corner.
or
Silly, WASPs don't screw in a light bulb, they screw in a hot tub.
or
From 2nd to 3rd because there's a shortstop in the middle.
or