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: Pathology
When osmotic fragility is normal, RBC's begin to hemolyse when suspended in saline ? 
Select and explain. 
A. 0.33%, B. 0.48%, C. 0.90%, D. 1.20%
B: 0.48%
Answer: B: 0.48% 
Explanation: Ans. is 'b' i.e., 0.48%