Which of the following statements about blood pH is true?
A. Carbon dioxide is a buffer that helps the blood pH remain around 7.4.
B. Carbonic acid is a waste product that makes blood pH deviate from 7.4.
C. 7.4 is a neutral pH, and the whole body needs to remain neutral to maintain homeostasis.
D. At a pH too far from 7.4, enzymes in the blood will stop functioning properly.