The correct answer is option 3: Goitre.

Goitre is a swelling of the thyroid gland in the neck, caused by a deficiency of iodine in the diet. Iodine is an essential nutrient that is crucial for the production of thyroid hormones, which regulate metabolism and play a role in growth and development.

The iodization of salt is a public health measure that involves adding iodine to salt to ensure that people consume an adequate amount of iodine in their diet. This is especially important in regions where iodine deficiency is common and can lead to the development of goitre and other related health issues.

Option 1: Diabetes mellitus is a metabolic disorder that affects blood sugar regulation. There is no direct link between iodization of salt and the prevention of diabetes mellitus.

Option 2: Tuberculosis is a bacterial infection that primarily affects the lungs. Iodization of salt does not have a direct impact on the prevention of tuberculosis.

Option 4: Anaemia is a condition characterized by a low level of red blood cells or hemoglobin in the blood. Iodization of salt is not directly related to the prevention of anaemia.

In conclusion, the iodization of salt is primarily done to prevent goitre, a condition