The correct option is B Pituitary
The pituitary is regarded as the “master” gland”. The hormones released by the anterior lobe of the pituitary gland stimulate the secretion of hormones by other target endocrine glands, e.g., thyroid stimulating hormone of the pituitary stimulates the thyroid gland to release the thyroid hormones. The parathyroid glands release parathormone and the pineal gland secretes melatonin. The hypothalamus is sometimes called the "master switchboard" as it secretes certain hormones that in turn, stimulate or inhibit the secretion of pituitary hormones.