Which Event Occurs When Parietal Cells of the Stomach Create

Which event occurs when parietal cells of the stomach create an enormous concentration difference in H⁺ across their plasma membranes?

A) H⁺ from a parietal cell is exchanged for K⁺ from the lumen of the gastric pit.
B) Carbonic anhydrase removes CO₂ from carbonic acid.
C) K⁺ is pumped back into the lumen of the gastric pit.
D) Cl^- is actively transported back into the bloodstream.
E) HCO₃^- from the blood is exchanged for Cl^- from the parietal cell.