The correct answer is ​Adrenal gland.

Key Points

• The adrenal glands are small glands located on top of each kidney.
• The adrenal cortex produces several hormones.
• The most important are aldosterone (a mineralocorticoid), cortisol (a glucocorticoid), and androgens and estrogen (sex hormones).
• These hormones help regulate metabolism, immune system, blood pressure, response to stress, and other essential functions.

Additional Information

• Thyroid gland:​
  • It produces hormones that regulate the body’s metabolic rate-controlling like heart, muscle, and digestive function, brain development and bone maintenance.
  • Its good functioning depends on a good supply of iodine from the diet.
• Thymus gland:​
  • The thymus is a lobed organ situated near the heart and, beneath the breastbone.
  • It is quite large at the time of birth but it gradually gets reduced with age.
  • The thymus provides the micro-environment needed for the maturation & development of T-lymphocytes.
  • The T-lymphocyte cells originate in the bone marrow but migrate or move to the thymus for maturation & development, hence if the thymus gland is removed from the newborn baby T-lymphocyte cells will not form.
• Corpus luteum:
  • ​The follicular cell is known as the corpus luteum.
  • The Corpus luteum is a follicular cell and gets filled with a yellow pigment called lutein.