Blood Has a PH Ranging from 7

Blood has a pH ranging from 7.35 to 7.45.Slight deviations from this can cause major problems, even death.You are doing an intense workout, and your skeletal muscle cells are producing metabolic acids such as lactic acid.Your blood pH does not drop significantly in spite of the metabolic acids released into the blood.You maintain a constant blood pH because

A) metabolic acids are neutralized in muscle cells before released into the blood.
B) metabolic bases are produced at the same rate by muscle cells to neutralize the acids.
C) the respiratory system removes excess H+ from the blood before the pH is lowered.
D) the body contains chemicals called buffers that resist changes in pH.
E) endothelial cells secrete excess H+ to prevent a decrease in pH.