Personally, I would do an introduction and conclusion for this question. It is 20 marks which is quite a lengthy essay. The intro only has to briefly discuss whether you agree or disagree with the given statement. It doesn't have to be specific, just a general overview. Then for your conclusion you essentially repeat the introduction. Just say that the writer effectively uses.... (whatever you have discussed) to convey whatever message.
Keep it short then you know you can't go wrong!