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
A young boy presented with a lesion over his right buttock which had peripheral scaling and central clearing with scarring. The investigation of choice would be: 
Select and explain. 
A. Tzank smear, B. KOH preparation, C. Biopsy, D. Sabourad's agar
C: Biopsy
Answer: C: Biopsy 
Explanation: C i.e. Biopsy