Goitre is caused due to the deficiency of:

Options

A. Carbohydrate
B. Protein
C. Iodine
D. Fatty acid

Answer

### Step-by-Step Solution:

1. **Understanding Goitre**: Goitre is a medical condition characterized by the abnormal enlargement of the thyroid gland, which is located in the neck.

2. **Identifying the Cause**: The enlargement of the thyroid gland is primarily caused by a deficiency of certain nutrients. In this case, we need to identify which nutrient is responsible for goitre.

3. **Analyzing the Options**:
- **Carbohydrate**: Not related to thyroid function or goitre.
- **Protein**: While important for overall health, it is not directly linked to goitre.
- **Iodine**: Essential for the production of thyroid hormones.
- **Fatty Acids**: Not related to thyroid function or goitre.

4. **Role of Iodine**: Iodine is a crucial mineral required for the synthesis of thyroid hormones, specifically T3 (triiodothyronine) and T4 (thyroxine). Without sufficient iodine, the thyroid gland cannot produce these hormones effectively.

5. **Conclusion**: Since iodine is necessary for the proper functioning of the thyroid gland and its deficiency leads to goitre, the correct answer is **iodine**.

### Final Answer:
Goitre is caused due to the deficiency of **iodine**.

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