***** NOT A TEACHER *****
(1) I believe that No. 2 is the correct answer.
(a) You are dealing here with the passive.
(b) The passive usually comes from an active sentence.
(c) The active sentence in your example was something like:
The people had elected him the CM of UP.
(i) That is changed to:
He had BEEN elected the CM of UP (by the people).
(a) As you know, the passive needs a form of "to be."
Student or Learner