_____________ Infrastructure, in the form of paved surfaces, disrupts water absorption and lowers water retention. This leads to disastrous levels of flooding which diminishes the biodiversity and impoverishes the people of the region. Land should be used mindfully to prevent water logging during heavy rains.

The passage discusses how infrastructure, such as paved surfaces, alters water's natural absorption and retention, which exacerbates flooding and threatens livelihoods and biodiversity. "Land should be used mindfully…" is the recommendation made at the end, reinforcing the notion that flooding is a result of human decisions.

Therefore, we're searching for a sentence that organically presents the notion that flooding is caused by infrastructure, and provides context for the discussion of water absorption and retention that follows.

Option C perfectly fits here. It essentially introduces the entire passage and sets the premise that infrastructure can influence flooding. The next sentences logically follow. 

The focus of the passage is not climate change here, it is flooding due to human interventions, so option A is not a good choice for opening statement, as it is very unrelated to the rest of the paragraph. Option B shifts the focus to rain intensity, which is again not the focus of the paragraph. Option D is a direct contradiction, as the paragraph clearly says that water retention is important. 

Thus, C is the correct choice here.