Botulism is

1. A

   Food-borne infection

   (a) Food-borne infection. Infection means live microbes multiply in the gut. Botulism is not typically an infection of that kind; the pre-formed toxin does the harm.

2. B

   Food-borne intoxication

   (b) Food-borne intoxication. Clostridium botulinum in poorly preserved food releases botulinum toxin. Illness follows ingestion of that toxin, so it is a food-borne intoxication, not an infection and not a water-borne disease. That is the official key.

3. C

   Water-borne infection

   (c) Water-borne infection. Classic water-borne infections are cholera or typhoid, not botulism.

4. D

   Water-borne intoxication

   (d) Water-borne intoxication. Botulinum toxin is not a water-supply poison in the exam sense; the vehicle is food, usually canned or fermented.

Summary. Official key is (b) Food-borne intoxication. Botulism is poisoning by a pre-formed bacterial toxin in food. It is not a water-borne illness and not an infection in the usual enteric sense. Infant botulism is a special gut-colonisation story, but the Prelims pairing remains food intoxication. Neighbouring names: staphylococcal food poisoning is also intoxication; salmonellosis is infection.