This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Heart, Circulation, and Blood, Subject name: Physiology
[{'content': 'Life span of RBC is: \nSelect and explain. \nA. 100 days, B. 120 days, C. 60 days, D. 160 days', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans: b (120 days) Ref: Ganong,22nd ed, p. 532In humans RBC survive in circulation for an average of 120 days.Remember Average life span of RBC- 120 daysAverage life span of neutrophil- 6 hoursAverage life span of platelets- 4 daysAverage life span of transfused platelets- 1 dayMonocytes as tissue macrophages-3 months (according to Bone marrow transplantation data.)', 'role': 'assistant'}]