What does the transition from the blue curve to the green curve represent in the context of hemoglobin?

• A. The transition represents hemoglobin's preference for hydrogen ion binding.
• B. The transition represents hemoglobin's inability to bind oxygen.
• C. The transition represents hemoglobin binding more CO2 in the lungs.
• D. The transition represents hemoglobin optimizing oxygen release in tissues.

Answer: (D)