Which gland in the human body is called the master gland?

The correct answer is Option (3) → Pituitary gland

The pituitary gland, a pea-sized gland at the base of the brain, is called the master gland because its hormones control several other endocrine glands: the thyroid (through TSH), the adrenal cortex (ACTH) and the ovaries and testes (FSH and LH). It also makes the growth hormone. It works in turn under the control of the hypothalamus.