Based on the context, what meaning is Brooks conveying by using a pun?
"Wow, thanks!" said Ivan. "That's more wisdom than I expected from a
shoemaker."
"Well, I'm not just any shoemaker," said Brooks. "You might say I deal in
matters of the sole."
A. He believes he gives good spiritual advice.
B. He does extra work for tips.
C. He secretly dislikes Ivan.
D. He specializes in the bottom parts of shoes.