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: Unknown
[{'content': 'Mycobacterium avium complex infections are common when the CD4+ counts in cells/mm3 are \nSelect and explain. \nA. 200, B. < 200, C. >50, D. < 50', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The CD4+ T-cell count can define the risk of infection with specific organisms. As a rule of thumb, bacterial and tubercular infections are more likely at higher CD4+ counts (>200 cells/mm3). Pneumocystis pneumonia usually strikes at CD4+ counts below 200 cells/mm3, while cytomegalovirus and Mycobacterium avium complex infections are uncommon until the very late stages of immunosuppression (CD4+ counts <50 cells/mm3).', 'role': 'assistant'}]