Oxygen hemoglobin dissociation curve

How does an increase in 2,3-DPG levels in the blood affect hemoglobin's oxygen affinity and its role in oxygen delivery?

1: Increased 2,3-DPG levels lead to a leftward shift in the oxy-hemoglobin dissociation curve, indicating increased oxygen affinity.
2: Elevated 2,3-DPG levels lead to an upward shift in the oxy-hemoglobin dissociation curve, reflecting an increase in hemoglobin’s carrying capacity for O 2 .
3: Increased 2,3-DPG levels cause a rightward shift in the oxy-hemoglobin dissociation curve, facilitating oxygen unloading.
4: Elevated 2,3-DPG levels increase hemoglobin's affinity for carbon dioxide rather than oxygen, facilitating CO 2 sequestration.