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
The kleihauer test for detecting fetal erythrocytes is based on the fact that : 
Select and explain. 
A. Adult erythrocytes are larger than those of foetus, B. hbA has higher 02 affinity than hbF, C. hbF is more resistant to acid elution, D. hbA takes erythromycin stain less than hbF
C: hbF is more resistant to acid elution
Answer: C: hbF is more resistant to acid elution 
Explanation: hbF is more resistant to acid elution