I would think of A first when considering my audience - not D because they'd know what I'm talking about if I'm their audience.
Glossary, is the name for the list of important words (and their definitions) at the end of a non-fiction work. They are meant to help the reader with understanding the material and can sometimes appear in fiction work as well.
Answer:
i believe its to introduce the theme
Explanation:
sorry if wrong
I believe the answer to your question is D