Which of the Following Statements About the Binding of Oxygen

Multiple Choice

Which of the following statements about the binding of oxygen to deoxyhemoglobin is correct

A) The binding of oxygen to Fe²⁺ in the first heme pulls the iron ion into the porphyrin ring, decreasing the affinity for the second oxygen.
B) The binding of oxygen to Fe²⁺ in the first heme pushes the iron ion out of the porphyrin ring, decreasing the affinity for the second oxygen.
C) The binding of oxygen to Fe²⁺ in the first heme pulls the iron ion into the porphyrin ring, increasing the affinity for the second oxygen.
D) The binding of oxygen to Fe²⁺ in the first heme pushes the iron ion out of the porphyrin ring, increasing the affinity for the second oxygen.
E) Oxygen does not bind to deoxyhemoglobin.