This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy of Skin, Subject name: Skin
[{'content': 'Which of the following is not a component of sebum? \nSelect and explain. \nA. Cholesterol, B. Wax, C. Glycerides, D. Propylene', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. (d) PropyleneRef: Rooks 8thed ch: 42.5', 'role': 'assistant'}]