Final answer:
The clearest way to revise Salina's research problem slide for better audience understanding is to include a title at the top of the slide.
Step-by-step explanation:
To make the information on Salina's slide more clear to the audience, the best option would be to include a title at the top of the slide (Option A). A title provides immediate context and tells the audience what the slide is about, which is essential for clarity. Additionally, it helps structure the presentation and guide the audience through the content. Although decreasing font size of the source, placing the source at the top, or swapping the order of text could have minor impacts on readability, none address clarity directly like adding a clear title does.