A. When they show a picture or video that makes the topic seem more real to the audience.
Visual aids, such as pictures or videos, are most effective in a speech when they enhance the audience's understanding and engagement with the topic. By presenting visual representations, the speaker can make the topic more tangible, relatable, and vivid for the audience. Visual aids can help in illustrating concepts, providing examples, or showcasing real-life scenarios, making the speech more compelling and memorable.