<prompt> A 10-yr-old boy presented with painful boggy swelling of scalp, multiple sinuses with purulent discharge, easily pluckable hair, and lymph nodes enlarged in occipital region. Which one of the following would be most help ful for diagnostic evaluation?Biopsy and Giemsa stainingBacterial cultureKOH mountPatch test, Gram staining Tzank smear  <response>: C i.e. KOH mount 