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 person having CD4 count of 200 presents with difficulty of breathing. The most probable diagnosis is? \nSelect and explain. \nA. Tuberculosis, B. Histoplasmosis, C. Candidiasis, D. Pneumocystis jiroveci', 'role': 'user'}, {'content': "Answer: D \nExplanation: Pneumocystis pneumonia is the most common oppounistic infection associated with AIDS. The risk of Pneumocystis jiroveci pneumonia among HIV- infected patients rises markedly when circulating CD4+ T cell counts fall below 200 cells/L. Tuberculosis in HIV patients occur when CD4 count is 100 cells/L. Ref: Manual of Emergency Medicine edited by Jon L. Jenkins, G. Richard Braen, 2004, Page 302 ; Harrison's Principles of Internal Medicine, Volume 2, Page 1267 ; Harrison's 17th ed chapter 182", 'role': 'assistant'}]