Final answer:
The sebaceous glands, skin, hair, and nails make up the integumentary system, which is the largest organ system in the body and responsible for protection, environmental sensing, and maintaining homeostasis.
Step-by-step explanation:
The sebaceous glands, skin, hair, and nails make up the integumentary system. The correct answer to your question is a) Integumentary. The integumentary system is the body's largest organ system and includes not only the skin but also associated structures such as hair and nails. It serves vital physiological functions like providing a protective covering for the body, sensing the environment, and helping the body maintain homeostasis. Both nails and hair add to the toughness and strength of the integumentary system due to the tough protein, keratin, that they contain.