This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Skin
[{'content': 'Acne vulgaris is caused by- \nSelect and explain. \nA. Staph aureus, B. Diphtheroids, C. Sweat gland hyperplasia, D. Obstruction to pilosebaceous duct', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. Obstruction to pilosebaceous duct', 'role': 'assistant'}]