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: Medicine
[{'content': 'A 30-year-old HIV positive patient presents with fever, dyspnoea and non-productive cough. The patient is cyanosed. His chest X-ray reveals bilateral, symmetrical interstitial infiltrates. The most likely diagnosis is - \nSelect and explain. \nA. Tuberculosis, B. Cryptococcosis, C. Pneumocystis carinii pneumonia, D. Toxoplasmosis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]