A. the absence of people suggests that something is very wrong with society.
All of the options are true statements. To answer this question it is important to look at what the question is asking. The key words in the question are impact and setting. Option B talks about the setting when it describes the weeds in the pavement, but this does not really have any profound impact on the story. Option C tells us about the temperature of the setting but it doesn't have any overall impact. Option D is more about characterization than it is about setting. Option A is the only one that has an overall impact on the setting. It introduces the society as dystopian.