Thyroxine, option 1, is the correct answer because it is a hormone produced by the thyroid gland that contains iodine. The thyroid gland uses iodine from the diet to make two main hormones which are Thyroxine (T4) and Triiodothyronine (T3). This is why it is essential to have iodine in our diet, as a deficiency can lead to diseases like goiter.

Option 2, Testosterone, is a male sex hormone which plays a key role in the development of male reproductive tissues. It does not involve iodine in its synthesis.

Option 3, Insulin, is a hormone made by the pancreas that allows your body to use sugar (glucose) from carbohydrates in the food that you eat for energy or to store glucose for future use. Insulin production does not utilize iodine.

Option 4, Adrenaline, also known as epinephrine, is a hormone and medication involved in regulating visceral functions (e.g., respiration). Adrenaline is produced in the adrenal glands, and like the other options, its production does not require iodine.