(a) Soap and detergent factory
(b) Lead battery manufacturing factory
(c) Plastic cup manufacturing factory
(d) Alcohol distillery
Correct option – ( d )
Explanation – alcohol distillery is responsible for lowering the pH of the river water and making it acidic . Alcohol is produced by the fermentation . When alcohol is oxidized into ethanoic acid then its side effect is that it changes the pH of the water and makes it acidic