**Core Concept**
Goitre refers to an enlargement of the thyroid gland, which can be caused by various factors including iodine deficiency, thyroiditis, or congenital anomalies. At higher altitudes, the prevalence of goitre is indeed higher due to the lower availability of iodine in the diet.

**Why the Correct Answer is Right**
The correct answer is related to the concept of altitude and iodine deficiency. At higher altitudes, the soil lacks iodine, which is essential for the synthesis of thyroid hormones. As a result, individuals living in these areas may have a diet deficient in iodine, leading to an increased risk of goitre. This is because the thyroid gland requires iodine to produce thyroid hormones, and a deficiency in iodine can lead to an enlargement of the gland.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not relate to the concept of altitude and iodine deficiency.

**Option B:** This option is incorrect as it is a cause of goitre, but not an example of how altitude is related to goitre.

**Option C:** This option is incorrect as it is a consequence of untreated goitre, but not an example of how altitude is related to goitre.

**Clinical Pearl / High-Yield Fact**
It is essential to note that iodine deficiency is a common cause of goitre, and individuals living in areas with iodine-deficient soil may require supplements to prevent this condition.

**Correct Answer:** D. Iodine deficiency at higher altitudes.