It presents background information needed to understand the text.
Explanation:
In the given story about how the narrator Noah was made to write a B & B letter by his mother to his grandparents. This led to the conflict of interest between the two as regards the issue of writing such a letter which he is not familiar with.
The first paragraph of the text reveals the background of how the letter came to be the main issue between the mother and her son. It presents the background information that reveals the main conflict between the two, without which we the readers, will be unable to understand the whole story.
I would choose either c or d, but c seems more logical to me, given the author is stating the visitor's purpose through figurative language, I would assume they would have a more metaphorical purpose to their cause.
