It's a reference to a previous speech in which he attempted to create an imaginary dilemma of having to choose between being electrocuted or eaten by a shark. That's the "clever question", because the boat salesman had never heard anyone ask that question.

The boat salesman was probably just being polite, because it's a stupid question. It's not a dilemma or even a contradiction. He's just making a sort of false equivalence and hoping that people are afraid of sharks so he can sell them his opinion on electric boats. In the same speech he also spent considerable time talking about how people ought to be afraid of sharks.

The addition of a snake and the credibility of his late uncle is a wonderful development of the story. He's probably going to add more stuff to it until he touches some topic that people actually care about..