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 child comes with a circular 3cm x 3cm scaly patchy hair loss with itching in the lesions. The investigation of choice is \nSelect and explain. \nA. Split skin smear, B. KOH mount, C. Gram stain, D. Tzanck smear', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Itchy lesions over head with hair loss likely suggestive of Tinea capitis and KOH mount of hairs is the investigation of choice.', 'role': 'assistant'}]