712. The famous Minamata disease in Japan is due to the accumulation of____________in fishes.

✅ The correct answer is option B.
Minamata disease, which can induce lethal or severely debilitating mental and physical effects, was caused by methylmercury‑contaminated effluent released into Minamata Bay by Chisso, Japan’s largest chemical manufacturer. It resulted in widespread suffering among those who unknowingly ate the contaminated fish.