Given the Properties of Myoglobin Shown in the O₂ saturation

Given the properties of myoglobin shown in the O₂ saturation curve below, what advantage does myoglobin confer to contracting muscles?

A) It pumps oxygen from hemoglobin in order to bind oxygen.
B) It contributes to the dark color of flight muscle in birds.
C) It increases the effectiveness of glycolytic muscles used in short bursts.
D) It releases bound oxygen at lower pO₂ conditions than hemoglobin does.
E) It binds oxygen at pO₂ values at which hemoglobin is releasing its bound O₂, facilitating O₂ delivery to muscle mitochondria.