42. Pepsin is a digestive enzyme that functions optimally at a pH of 2, an environment highly concentrated with H* ions. In contrast, most enzymes found in the human body have optimal pH values ranging from 6 to 8. The extreme acidity of pH 2 would typically cause most enzymes to denature, leading to a sharp drop in activity, because the high concentration of H+ ions disrupts the weak interactions crucial for stabilizing the protein's functional shape. Which statement below best describes the mechanism by which Pepsin is specifically adapted to maintain its maximum catalytic activity in the stomach environment? (A) Pepsin uses strong covalent bonds (peptide bonds) to form its active site, which cannot be broken by H+ ions, unlike the weak bonds found in other enzyme active sites. (B) Pepsin's △G (Free Energy change) for its specific catabolic reaction shifts to a highly negative value at pH 2, thereby increasing the spontaneous rate of the reaction independent of structure. (C) The structure of Pepsin minimizes the use of the most electronegative elements. (Oxygen and Nitrogen) in its regulatory sites, making it insensitive to competitive inhibition by H+ ions. (D) Pepsin has evolved to significantly raise the overall activation energy (EA) barrier of its substrate at neutral pH, forcing the reaction to only proceed effectively when thermal energy is supplied by the acidic environment. (E) The amino acid sequence of Pepsin results in a unique three-dimensional configuration that prevents the high concentration of H+ ions from disrupting the crucial weak interactions (such as ionic bonds and hydrogen bonds) necessary for its active shape.