Correct Answer: (c) Endocrine glands
Solution:Endocrine or internally secreting glands are ductless glands since they lack excretory ducts. Endocrine glands secrete their products, hormones, directly into the blood rather than through a duct. The major glands of the endocrine system include the pineal gland, pituitary gland, thymus, thyroid gland, parathyroid gland and adrenal glands etc.