question_answer 60)

  (I)?                                        (II)                                   (III) (a)                   (b) (c)                    (d)

Answer:

  (d) More the number of electron-withdrawing  groups at o- and ^-positions w.r.t. the Cl atom, more reactive is the compound. Thus, option (d) is correct, i.e., I < II < III.