The claim that the excerpt most clearly supports seems to be:
D. Without humanity's presence, New York City would quickly deteriorate.
Explanation:
This excerpt taken from Alan Weisman's "The City Without Us" discusses how the human presence keep New York from becoming a disastrous chaos. As the author explains, without power and people to pump the water out, the subway systems of New York would be completely flooded. If it rains, it would only take some hours for it to be underwater; if it doesn't, just a couple of days. The author is showing readers that the city only functions because of the people who work to ensure it. If humans were to disappear, it wouldn't be long before the world became wild and nature claimed everything man has ever built.
