Explanation

Methanol itself is only mildly toxic, but in the liver the enzyme alcohol dehydrogenase oxidises it first to formaldehyde (methanal) and then to formic acid. Formaldehyde is highly reactive and coagulates protoplasm, causing tissue damage, metabolic acidosis and, characteristically, optic nerve damage leading to blindness. It is not oxidised to acetic acid or carbon monoxide in this pathway. The answer is (B).