The correct answer is option 2: Water pollution. Minamata disease, which occurred in 1956, was caused by water pollution. Minamata disease is a neurological disorder caused by the consumption of seafood contaminated with methylmercury. Methylmercury entered the water bodies through the industrial discharge of mercury-containing wastewater into Minamata Bay in Japan. The mercury compounds discharged into the water underwent a process called biomagnification, where they accumulated in the food chain, with the highest concentrations found in fish and shellfish. When humans consumed the contaminated seafood, they ingested high levels of methylmercury, resulting in mercury poisoning and the onset of Minamata disease. This tragic incident highlighted the devastating impact of industrial pollution on ecosystems and public health.