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: Gynaecology & Obstetrics
Lifespan of the fetal RBC approximately is 
Select and explain. 
A. 60 days, B. 100 days, C. 80 days, D. 120 days
C: 80 days
Answer: C: 80 days 
Explanation: The lifespan of fetal red cells is 80 days and Rh factor is developed by 38 days.