This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mycobacterial Infections, Subject name: Dental
A young boy presented with a lesion over his right buttock, which had peripheral scaling with central scarring. The investigation of choice would be? 
Select and explain. 
A. Tzanck smear, B. KOH preparation, C. Biopsy, D. Sabourad's agar
C: Biopsy
Answer: C: Biopsy 
Explanation: Central clearing: T. Corporis - KOH smear Central scarring: Lupus vulgaris - Biopsy Central crusting: Leishmaniasis - LT body demonstration