Answer:
a Tell a story about rappelling into a cavern that can't be reached any other way.
Explanation:
Talking about accidents might actually have the opposite effect, even if you mean to ensure that rappelling is safe. Fact stating can be uninteresting or even boring. And asking someone if they've done something is not encouraging in any ways.
An exciting story about a "secret location" with a sense of adventure, on the other hand, is very interesting on its own and the use of rappel in this story might make rappelling much more interesting.
