The question asks why residents **did not complain**, even though their water became murky. We need an explanation for the lack of complaints.
Option analysis:
A. Fluctuating rainfall over 10 years.
→ Irrelevant to residents’ complaints.
B. No expert advice has been obtained on whether the water is toxic.
→ Explains that residents may not know if there’s a real problem. Could be a reason for not complaining.
C. Fonidol’s arrival was part of a well-supported economic-development effort.
→ Yes! Residents may not complain because the company’s presence is seen positively and the community strongly supports it. This directly explains the lack of complaints.
D. Higher water fees.
→ Unrelated to complaints about water quality.
E. Gas reserves expected to run out in 40 years.
→ Irrelevant to why people aren’t complaining now.
Correct answer: C