Final answer:
The thyroid gland uses iodine to produce hormones, and iodine deficiency can lead to goiter and other health issues.
Step-by-step explanation:
The endocrine gland that requires iodine to produce its hormone is the thyroid gland. The thyroid is unique for its ability to absorb iodine and use it to create the hormones thyroxine (T4) and triiodothyronine (T3). These hormones are essential for regulating metabolism, growth, and development. A deficiency in iodine can lead to a condition called goiter, which is the enlargement of the thyroid gland, as well as other disorders like cretinism. Thus, the correct answer to the question is (A) Thyroid.