The correct answer is option 3 - Pituitary. The pituitary gland, also known as the "master gland," is responsible for producing and releasing various hormones, including the growth hormone or somatotropin.

Option 1 - Adrenal: The adrenal glands are responsible for producing hormones such as adrenaline and cortisol. They do not produce the growth hormone.

Option 2 - Pancreas: The pancreas produces insulin, which helps regulate blood sugar levels. It does not produce the growth hormone.

Option 4 - Thyroid: The thyroid gland produces hormones like thyroxine, which regulate metabolism and growth. While it does play a role in growth, it does not directly produce the growth hormone.

Therefore, the correct answer is pituitary gland, located at the base of the brain, which is specifically responsible for producing the growth hormone or somatotropin.