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: Medicine
2 zeta and 2 gamma chains are present in which hemoglobin 
Select and explain. 
A. Hb Portland, B. Hb gower I, C. Hb gower II, D. HbA2
A: Hb Portland
Answer: A: Hb Portland 
Explanation: Hb portland - 2 zeta & 2 gamma.
Hb Gower I - 2 zeta & 2 epsilon.
Hb gower II - 2 alpha & 2 epsilon.