This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood: RBCs, Anemia, and Polycythemia, Subject name: Physiology
Longest life span among following - 
Select and explain. 
A. RBC, B. Plalalets, C. Neutrophils, D. Macrophages
D: Macrophages
Answer: D: Macrophages 
Explanation: Ans. is 'd' i.e., Macrophages Life span of blood ceilsRBC: 120 daysPlatelets : 7-12 daysMonocytes (in circulation) : 1-3 daysMacrophages (in tissues) : Months-yearsNeutrophils (in circulation) : 4-8 hrsNeutrophils (in tissue) : 2-5 daysShort lived lymphocytes : 2 weeksLong lived lymphocytes : Upto 3 years