This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skin, Subject name: Pharmacology
[{'content': 'All trans retinoic acid is used topically for - \nSelect and explain. \nA. Acne vulgaris, B. Lupus vulgaris, C. Alopecia areata, D. Androgenic alopecia', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Acne vulgaris * All-trans retinoic acid (Tretinoin) is used topically, while 13-cis retinoic acid (Isotretinoin) is given orally for acne.", 'role': 'assistant'}]