Which of the following hormones contains iodine?

Thyroxine, the hormone of the thyroid gland, is an iodinated derivative of the amino acid tyrosine; each molecule contains four iodine atoms (tetraiodothyronine, $T_4$).
This is why iodine is essential in the diet; its deficiency causes hypothyroidism and goitre, and iodised salt is used to prevent it.
Insulin is a polypeptide hormone, testosterone is a steroid hormone and adrenaline is an amine derived from tyrosine; none of them contains iodine.
Hence the hormone that contains iodine is thyroxine.