44. Cholera toxin, a protein produced by a gram-negative bacterium vibrio cholerae, is responsible for the characteristic symptoms of cholera: extensive loss of body water and Na⁺ through continuous, debilitating diarrhea. If body fluid and Na⁺ are not replaced, severe dehydration results； untreated, the disease is often fatal. What is the effect of cholera toxin in the intestinal cells? (A) Increase GTP hydrolysis. (B) Persist activation of G protein. (C) Increase the degradation of cGMP. (D) Increase the rate of phophatidylinositol turnover. (E) Open the chloride channels on the membrane of intestinal cells.