Explanation:

- Option 1: Bacterial meningitis

- This is a serious infection of the membranes covering the brain and spinal cord. Not a form of malnutrition.

- Option 2: Diarrhoea

- A symptom caused by infection or other causes, leading to watery stools. It can be a result of malnutrition, but is not itself a malnutrition disorder.

- Option 3: Pneumonia

- This is a lung infection causing difficulty in breathing. It is not a form of malnutrition.

- Option 4: Kwashiorkor

- Kwashiorkor is a severe form of malnutrition, mostly seen in infants and toddlers, especially after weaning up to age 5.

- It results from a lack of protein in the diet, causing swelling, irritability, and an enlarged liver.