Which of the following would be the most help in defining the main idea of a presentation?

A) Determine the seating arrangement of the presentation based on advantages
B) Limit the scope of the message to three key ideas
C) Determine how much time is available compared to the amount of material
D) Identify the essential message points that are important to the presenter
E) Write a one-sentence summary that links to the audience's frame of reference

Writing a one-sentence summary that links to the audience's frame of reference would be the most helpful in defining the main idea of a presentation as it provides a clear and concise statement that connects with the audience's interests and needs. This will help the audience understand the purpose and focus of the presentation from the start. The other options provide helpful tips for organizing and delivering the presentation but do not directly address defining the main idea.