You are answering a USMLE-style medical question. Question: A 64-year-old man comes to the physician with a 1-week history of sore mouth. He says that swallowing is not painful. He has had asthma for more than 20 years. His only medication is a high-dose combination salmeterol/fluticasone inhaler. His temperature is 37.1°C (98.8°F), pulse is 74/min, respirations are 14/min, and blood pressure is 125/65 mm Hg. A photograph of his oral mucosa is shown. Indirect mirror examination of the posterior oropharynx, larynx, and hypopharynx shows no abnormalities. Which of the following is the most appropriate next step in management? Options: A) Fluconazole B) Isotretinoin C) Nystatin D) Penicillin V Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.