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': 'Treatment of choice of Nodulocystic Acne is : \nSelect and explain. \nA. Erythromycin, B. Isoretinoin, C. Tetracycline, D. PUVA', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. is \'b\' Isotretinoin [Ref Harrison 16/e, p 295 (Page 3151 Rexburg\'s 16/e Page 1561According to this table 3 choice are correct but Harrison says "that severe nodulocystic acne not responsive to oral antibiotics, hormonal therapy or topical therapy may be treated with synthetic retinoid, Isotretinoin."', 'role': 'assistant'}]