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
True statement about hemoglobin is ? 
Select and explain. 
A. Each hemoglobin molecule is made of 4 polypep tides of each subunit, B. Two alpha and two beta subunits having a 02 attached to each subunit, C. Each hemoglobin molecule binds to only one 02 molecule, D. Each hemoglobin has one heme molecule
A: Each hemoglobin molecule is made of 4 polypep tides of each subunit
Answer: A: Each hemoglobin molecule is made of 4 polypep tides of each subunit 
Explanation: Ans. is 'a' i.e., Each hemoglobin molecule is made of 4 polypeptides of each subunit