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': "The test likely to help in diagnosis of a patient who presents with an itchy annular plaque on the face is – \nSelect and explain. \nA. Gram's stain, B. Potassium hydroxide mount, C. Tissue smear, D. Wood's lamp examination", 'role': 'user'}, {'content': 'Answer: B \nExplanation: The clinical picture is suggestive of a fungal infection most likely Tinea fascitis, KOH preparation is performed on scaling skin lesion when fungal etiology is suspected. Microscope examination after KOH digestion will show fungal hyphae.', 'role': 'assistant'}]