The correct answer is C. An artist's brochure describing his artwork and what it means.
Explanation
An expository text is a type of text in which, as its name indicates, a description of something, in particular, is made. This type of text specializes in giving prominence to the characteristics of said object. According to this definition, it can be said that an example of expository text is "an artist's brochure describing his artwork and what it means", because in it he can present his work and explain what it is about. Therefore, the answer is C.