The correct answer is option 2: the base of the brain. The pituitary gland, also known as the master gland, is located at the base of the brain in a small depression called the sella turcica. It is connected to the hypothalamus by a stalk-like structure called the infundibulum. The pituitary gland is responsible for producing and releasing various hormones that regulate important functions in the body. These hormones include growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormone, prolactin, and antidiuretic hormone. It plays a crucial role in controlling the activity of other endocrine glands and is essential for maintaining homeostasis in the body. It is important to note that the pituitary gland is not located in the heart, neck, or abdomen.