Final answer:
The main difference between impromptu and extemporaneous debates is the preparation time allowed. Impromptu debates require participants to prepare in a very short time, while extemporaneous debates allow for longer preparation with research materials. Impromptu debates require less preparation time than extemporaneous debates.
Step-by-step explanation:
The difference between an impromptu debate and an extemporaneous debate lies in the amount of time participants have to prepare. In an impromptu debate, participants have much less time to prepare compared to an extemporaneous debate.
Impromptu debates typically involve participants receiving a topic or motion just before the debate begins and they must formulate arguments and rebuttals on the spot. On the other hand, in an extemporaneous debate, participants are given some time, usually a few minutes, to prepare their arguments and research the topic before the debate begins.
Therefore, option B is the correct answer as it accurately describes the difference between impromptu debates and extemporaneous debates based on the preparation time participants have.