Answer:
The kind of supporting material Jeff used in his introduction is hypothetical example.
Explanation:
A hypothetical example is an imaginary story that makes a general point. It also helps convey an idea or explanation more simply in case the speaker is explaining a complicated topic. Hypothetical examples help make something more realistic or relatable. In Jeff's case, the example was given in the introduction to his speech, making the audience curious. The situation is interesting and frightening at the same time. Now the listeners are hooked, excited about whatever it is the Jeff has to say about that situation.
