The correct option is C Parathyroid gland
The endocrine system includes all of the organs that function exclusively as endocrine glands - such as the thyroid gland, parathyroid gland, pituitary gland, adrenal glands, pancreas, thymus, as well as organs that secrete hormones in addition to other functions. Endocrine glands lack ducts and thus must secrete into surrounding blood capillaries, unlike exocrine glands, which secrete their products into a duct.
Sweat glands, sebaceous glands and salivary glands are all exocrine glands and pour their secretions with the help of ducts at the target site. Gall bladder is a small organ in the human body that stores bile and releases it into the small intestine through the bile duct.