The key word in this question is "guarantees". I can speak from experience that using a PowerPoint does not guarantee that the audience will understand everything included or end on schedule. Anyone who has sat through a PowerPoint-driven lecture can tell you that being engaged and excited depends a lot more on content and delivery than the fact that a PowerPoint was used.
While a PowerPoint may help the presentation stay on schedule, be clear and understood, and keep the audience engaged, the mere fact that a PowerPoint was used guarantees none of these.
Answer is D
