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
The polypeptide chains of hemoglobin A are composed of 
Select and explain. 
A. 1 alpha, 3 beta, B. 2 alpha, C. 2 alpha, 2 beta, D. 1 alpha, 2 beta, 1 delta
C: 2 alpha, 2 beta
Answer: C: 2 alpha, 2 beta 
Explanation: Hemoglobin A has 2 alpha and 2 beta chains.
HbA2 has two alpha and two delta chains.