Without Mitochondria, RBCs Are Relatively Inefficient in Terms of Energy

Without mitochondria, RBCs are relatively inefficient in terms of energy production. However, there is an advantage to RBC function. What is this advantage?

A) It ensures that its iron component will interact with the plasma protein transferrin.
B) It stimulates the conversion of yellow bone marrow to red bone marrow.
C) It stimulates the absorption of vitamin B₁₂.
D) It ensures that its iron component is converted to bilirubin.
E) It ensures that any oxygen the RBCs absorb will be delivered to peripheral tissues.