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
Hb - Barts is 
Select and explain. 
A. α2 β2, B. αo β4, C. αo γ4, D. α2 γ2
C: αo γ4
Answer: C: αo γ4 
Explanation: Option a - HbA
Option b - HbH
Option d - HbF.