This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infection, Subject name: Medicine
The most common oppounistic infection observed in patients with AIDS is - 
Select and explain. 
A. Atypical mycobacteria, B. Haemophilus influenzae, C. Pseudomonas aerugiosa, D. Pneumocystis carinii
D: Pneumocystis carinii
Answer: D: Pneumocystis carinii 
Explanation: The symptoms of PCP include Fever Cough Difficulty breathing Chest pain Chills Fatigue (tiredness) In people with HIV/AIDS, PCP symptoms usually develop over several weeks and include a mild fever. In people who have weakened immune systems for reasons other than HIV/AIDS, PCP symptoms usually develop over a few days, often with a high fever. Ref Harrison20th edition pg 1078