Answer: B) Rachael should give a brief, credibility-building explanation of her experience with the topic.
Explanation: By giving a brief explanation, Rachael avoids appearing speaker-centered and also builds credibility. This makes the audience believe they can trust her. Nobody wants to listen to someone give a speech about a topic they are not familiar with. Establishing that she is an authority on the topic will inspire confidence in her audience and motivate them to listen to her.
Option A, avoiding describing her experience will achieve the opposite of this and she risks the audience losing interest by giving a long detailed explanation of her experiences.