21. When titrating a weak monoprotic acid with NaOH at 25℃, the (A) pH will be less than 7 at the equivalence point. (B) pH will be equal to 7 at the equivalence point. (C) pH will be greater than 7 at the equivalence point. (D) titration will require more moles of base than acid to reach the equivalence point. (E) titration will require more moles of acid than base to reach the equivalence point.