Carbon Monoxide Facts The Fact That Carbon Monoxide Reduces Hemoglobin's Oxygen-carrying Capacity Would Indicate What?

The fact that carbon monoxide reduces hemoglobin's oxygen-carrying capacity would indicate what? - carbon monoxide facts

Cause hemoglobin, A. differently in different gas
As hemoglobin can not bind carbon monoxide
C. Carbon dioxide is an abnormal
D. Carbon monoxide competes with oxygen for the same binding site of hemoglobin
E. Union of different gases is regulated by a variety of enzymes