Hello. This question is incomplete. You did not provide the text to which this question refers, nor did you provide the answer options. This makes it impossible for that question to be answered. However, I will try to help you in the best possible way.
The main purpose of a text is the effect that the author wants to achieve on the reader. For example, a text that addresses a political issue, wants to alert the reader to the country's politics, a text about social inequality wants to show the reader the social problems resulting from that inequality, a descriptive text wants to describe something to the reader.
In this case, to answer your question, you must read the text, identify what the author is trying to show you through that text and how the example achieves this purpose, that is, how the example shows what the author wants to show through text.