This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infectious Disease, Subject name: Pathology
A child of 7-8yrs of ages; c/o scalp swelling, alopecia: 
Select and explain. 
A. Gram staining, B. KOH staining of the scrapings, C. PAS staining, D. Blood culture
B: KOH staining of the scrapings
Answer: B: KOH staining of the scrapings 
Explanation: Ans. is 'b' KOH staining of scrappingThe child is suffering from tinea capitis.It is a fungal infection which requires KOH scrapping for diagnosis.