The correct option is D D
(A) Simple colloid goitre - If there is deficiency of iodine in food then thyroid tries to absorb more and more iodine from the blood and increases its size. This is called simple goitre.
(B) Thymus gland secretes a peptide hormone called thymosin or thymin hormone. Thymus provide cell mediated immunity (cellular immunity) and also promote production of antibodies to provide humoral immunity. So, thymus is also called "training school of t-lymphocytes".
(C) Exopthalmic goitre is a form of hyperthyroidism, characterised by enlargement of the thyroid gland, protrusion of the eyeballs, increased basal metabolic rate, and weigth loss. It is also called Graves' disease.
(D) In adults, hypothyroidism causes myxoedema.