21. Which one of the following descriptions for the Beer’s law is incorrect? (A) Beer’s law is ordinarily represented as A =εbs. (B) For a mixture, the total absorbance at a λ=the sum of individual absorbance if there is no intermolecular interaction. (C) Beer’s law is more suitable for concentrated solutions. (D) Negative deviations are always observed if polychromic radiations are used. (E) The b term in the equation of item (a) means the optical length.