4. Buffers have all of the following characteristics EXCEPT: (A) They have relatively flat titration curves at the pH(s) where they buffer. (B) They resist changes in their pH as acid or base is added. (C)They are typically composed of a weak acid and its conjugate base. (D) They buffer best for polyprotic acids half-way between the two pKa values. (E)Buffer where the amounts of conjugate base are nearly equivalent to the amounts of weak acid.