Which of the following scenarios describes the cardiorespiratory response to exercise?
A. An increase in cardiac output increases oxygen delivery to working muscles and increases carbon dioxide produced, which increases breathing rate
B. The increased carbon dioxide production in the body increases breathing rate, which increases cardiac output and slows heart rate
C. An increase in breathing rate increases the need for oxygen but decreases the availability of oxygen to the working muscles
D. Arteries constrict to pump the needed blood and oxygen to the working muscles