In 2012, Lance Armstrong Was Stripped of His Record-Setting, Seven

In 2012, Lance Armstrong was stripped of his record-setting, seven Tour de France titles and banned for life from competitive cycling because of his alleged use of performance-enhancing drugs (PEDs) . One of the PEDs Armstrong was accused of taking is erythropoietin (EPO) . Why would systematic use of this PED give Armstrong an unfair advantage in a bike race?

A) EPO stimulates formation of new capillary beds in skeletal and heart muscle.
B) EPO stimulates the formation of new alveoli in the lungs.
C) EPO stimulates red blood cell production by the bone marrow.
D) EPO increases cardiac output by stimulating the ventricles to contract more strongly.
E) EPO stimulates growth of skeletal muscle tissue.
F) EPO stimulates the production of more mitochondria in cardiac muscle cells.