Answer:
D.
Step-by-step explanation:
Narrowing the topic of the speech is an important aspect of delivering a good speech.
A speaker can narrow his/her speech based on four basic principles. They are purpose, audience, time frame, and, context.
In the given case, Sarah had narrowed her topic of speech to "How to Train your Dog?" From the given brainstorming list of questions of Sarah, the questions that she can eliminate are 1-4 (option D). As the topic suggests the speech should be related to training the dogs. And questions 1-4 are some of the off-topic questions that can consume more time of the speaker and will eliminate the possibility of giving an effective speech.
Questions 6-10 are related to the topic of training the dogs, so Sarah can speak on these questions and eliminate questions 1-4.
So, the correct answer is option D.