© The time and the place for such a large event are subject to the approval of the mayor’s office.
(D) The time and place for such a large event are subject to be approved by the office of the mayor.
The answer is © for some reason. I am confused why it’s C because it states, " approval of the mayor’s office".
Not sure what’s wrong with “approval of the mayor’s office.”
D is passive while C is active. Since I see no problem with C, it is a better answer than D.
Idiomatically, “subject to” must be followed by a noun phrase rather than an infinitive verb or a clause. @Woandering - the part of © that matters (“the approval of the mayor’s office”) is not “active” at all; in fact, it’s not a clause as it has no verb.
Oh I see now. Thanks for clearing it up.