What is the primary reason gamma subunits in fetal hemoglobin enhance oxygen affinity?

• A. Gamma subunits bind oxygen more tightly than beta subunits.
• B. Gamma subunits are more flexible, allowing easier oxygen binding.
• C. Gamma subunits have a lower affinity for BPG compared to beta subunits.
• D. Gamma subunits increase the overall size of hemoglobin, allowing more oxygen to bind.

Answer: (C)