During Exercise, O2 Is Depleted in Muscle Tissue

During exercise, O2 is depleted in muscle tissue. What effect would this have on internal respiration?

A) There would be increased diffusion of O2 out of the blood and into the muscle tissue.
B) There would be decreased diffusion of O2 out of the blood and into the muscle tissue.
C) There would be increased diffusion of O2 out of the blood and into the lungs.
D) There would be decreased diffusion of O2 out of the blood and into the muscle tissue and a decrease in heart rate to bring more O2 to the exercising muscle.