Your friend asks you to create a visual text to go along with a presentation. What is a visual text?

A visual text communicates meaning primarily through visual elements. This can include images, symbols, graphics, and the visual arrangement of words.

Let's evaluate the given options:

• a. A visual text is a still image of something. A still image (like a photograph, diagram, or chart) is a common type of visual text. While not all visual texts are only still images (e.g., videos are also visual texts), a still image is a valid example and component of visual text.
• b. A visual text is an image that cannot have words. This is incorrect. Many visual texts, such as infographics, advertisements, or comics, combine images with words to convey meaning.
• c. A visual text is only a chapter book with pictures in it. This is incorrect. Visual texts encompass a much broader range of media than just chapter books, including posters, maps, charts, and more.
• d. A visual text is an image that must have words. This is incorrect. Many visual texts, like symbols or certain photographs, convey meaning without any accompanying words.

Among the given choices, option (a) is the most accurate description of a common form of visual text, as still images are frequently used as visual texts in presentations and other contexts. The other options contain restrictive or false statements.

The final answer is $\boxed{\text{a}}$