Answer:
D. better understand the theme of a text.
Explanation:
A diagram is a graphic aid which includes essential information from the text you are reading and, as a result, provides a better understanding of it. This is an excellent way to help readers to remember main ideas even from the more complex information.
Even though all the alternatives are essential items in the process of reading comprehension, the suitable answer is letter D: better understand the theme of a text.
