When : When are you going to be home from the party?
What: What do you think would happen if I went to this party ?
Who: Who do you think is going to be at the party?
Why: Why do you think these people are going to be at the party?
The answer is (d.) choose only the visuals that are easily understood.
The main purpose of the visual aids is to help improve the understanding of the audience to the presentation. It clarifies and reinforce the key points of the topic. So it's important to choose the appropriate visual that could help the presentation easily understood.
