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: Dental
[{'content': "A young boy presented with lesion over his right buttock which had peripheral scaling and central scarring. The investigation of choice would be – \nSelect and explain. \nA. Tzank Smear, B. KOH preparation, C. Biopsy, D. Saboraud's agar", 'role': 'user'}, {'content': 'Answer: C \nExplanation: The boy is having lupus vulgaris because the lesions have central scarring.\nCentral Scarring is a feature of lupus vulgaris.\nDiagnosis of lupus vulgaris is confirmed by Biopsy.\n\nRemember\xa0\nFeature \xa0 \xa0\xa0\xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0\n\nCentral clearing \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0\nCentral Scarring \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0\xa0\nCentral Crusting \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0\n\nDisease\n\nTinea corporis \xa0\n\xa0Lupus Vulgaris\xa0\n\xa0Leishmaniasis \xa0\xa0\n\n\xa0Investigation\n\nKOH Smear\nBiopsy\nLD body demonstration', 'role': 'assistant'}]