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: Dental
[{'content': 'A 7 year old boy with boggy swelling of the scalp with multiple discharging sinuses with cervical lymphadenopathy with easily pluckable hair. What would be done for diagnosis – \nSelect and explain. \nA. Pus for culture, B. KOH mount, C. Biopsy, D. Patch test', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Boggy swelling, multiple discharging sinus, cervical lymphadenopathy and easily pluckable hair suggest the diagnosis of Keroin type of Tinea capitis.\n\n\nTissue specimens, such as skin scarpings, are generally examined as wet mounts after treatment with 10% KOH.\nKOH (alkali) digests cells and other tissue materials, enabling the fungus elements to be seen clearly.\nPeriodic acid Schiff (PAS) and methenamine silver stains are valuable methods for the demonstration of fungal elements in tissue sections.', 'role': 'assistant'}]