Therefore option C, Thyroid gland, is factually consistent with the stem, the marked correct index, and the explanation.✅ Correct Answer: C — Thyroid gland Thyroxine (T4) and Triiodothyronine (T3) are produced by the Thyroid Gland, a butterfly-shaped gland located at the front of the neck. Pituitary gland — Pituitary releases TSH (Thyroid Stimulating Hormone) which stimulates the thyroid to produce thyroxine, but it doesn't produce thyroxine itself. Adrenal gland — Adrenal gland produces Adrenaline (epinephrine), Cortisol, Aldosterone; not thyroxine. Parathyroid gland — Parathyroid glands (4 small glands behind thyroid) produce PTH (Parathyroid Hormone) which regulates calcium levels; not thyroxine. 📝 Important Note: Thyroid gland = Thyroxine (T3, T4). Hyperthyroidism = excess thyroxine (fast metabolism, weight loss). Hypothyroidism = low thyroxine (slow metabolism, weight gain). Goitre = enlarged thyroid from iodine deficiency. TSH from pituitary controls thyroid.