This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc. (W.B.C), Subject name: Pathology
[{'content': 'Serious infections can occur when absolute neutrophil count decreases below? \nSelect and explain. \nA. Less than 500/ul, B. Less than 800/ul, C. Less than 1000/u, D. less than 2000/ul', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Less than 500/ul(Ref: Robbins 9th/pg 583)Serious infections are most likely when the neutrophil count falls below 500 per mm3.', 'role': 'assistant'}]