The correct answer is C. captions.
A caption is a brief explanation or description that appears below an image, photograph, or illustration. It is usually written in a smaller font than the main text and is intended to provide additional information or context for the image.
A topic is the subject or main idea of a piece of writing or discussion.
A title is a word or phrase that identifies a book, article, or other work.
A heading is a word or phrase that appears at the top of a page or section of text and indicates the topic of that section.
In the case of cartoons, the captions are often used to provide humor or commentary on the image. They can also be used to provide additional information about the image, such as the name of the artist or the date the image was created.