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: Biochemistry
In sickle cell anemia, replacement is - 
Select and explain. 
A. Val by glu in β6, B. Glu by val in β6, C. Hist val β8, D. 6α
B: Glu by val in β6
Answer: B: Glu by val in β6 
Explanation: In sickle cell anemia glutamate is replaced by valine at position 6 of β-chain.