Which of the following hormones contains iodine?

Correct answer: (c) Thyroxine

Explanation

Thyroxine (T4), secreted by the thyroid gland, is an iodine-containing hormone; its active form triiodothyronine (T3) also has iodine.

It regulates basal metabolic rate and the metabolism of carbohydrates, fats and proteins.

Distractors lack iodine: testosterone (steroid), adrenaline (amine), and insulin (protein).