This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fungal infections, Scabies, Pediculosis, Subject name: Dental
A10 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,wof would be most helpful for diagnostic evaluation 
Select and explain. 
A. Biopsy and giemsa staining, B. Bacterial culture, C. KOH mount, D. Patch test, gram staining and Tzank smear
C: KOH mount
Answer: C: KOH mount 
Explanation: TINEA CAPITIS Inflammatory tinea capitis (kerion):- Caused by zoophilic dermatophyte (e.g., M. canis), which elicit intense inflammation. Presents as a boggy swelling with pustulation. Often, the pus discharges from multiple orifices. Hair from such a swelling is easily and painlessly pluckable. Lymphadenopathy (especially occipital) invariable. Investigations:- Potassium hydroxide (KOH) scraping KOH mount: fig:-A: spores inside hair shaft in tinea capitis. Ref:- Neena Khanna; pg num:-284