The correct answer is "object complement", because it follows a direct object (in this case "the normally flat land") and renames it or states what it has become. It cannot be "predicative nominative" because "hilly" is not a noun, "direct object" here is "the normally flat land", and a predicate adjective follows a linking verb (for example, She is PRETTY.) So the only option left is "object complement".
I think it is A) Reference
Because piggy wants to be heard he has something to say but nobody listens to piggy.
