This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
Lifespan of neutrophils is 
Select and explain. 
A. 6 hours, B. 1 day, C. 7 days, D. 120 days
A: 6 hours
Answer: A: 6 hours 
Explanation: The average half-life of a neutrophil in the circulation is 6 hoursRef: Ganong's Review of Medical Physiology Twenty-Third Edition Page No: 64