What does a measure of your cardiorespiratory endurance tell a fitness professional

The answer would be "Your aerobic fitness or how efficiently your heart is working" or "A."

Measuring cardiorespiratory endurance simply means doing a test that measures the ability of your body to uptake and utilize oxygen (thus "aerobic") 
its called cardiorespiratory because your respiratory system uptakes the oxygen (and exhales the CO2) and your cardiovascular system sends it to the muscles needing the oxygen.

Source(s): Google/Yahoo