Now of course you may not actually think that the utilitarian justification is persuasive, but it would not be appropriate to refrain from giving it for that reason. In an essay, and some of the longer AT questions, a somewhat different approach is required. In such questions, you need to display your understanding of the relevant course-material, but often you need also to show that you are aware of the implications of this material. The answer to this depends on the sort of question being tackled, as pointed out above. However, there is an appropriate balance to be struck between original content and utilisation of course content.
Philosophical writing requires a high standard of English expression and careful reasoning.
A common mistake that novice students make is simply to report on what they believe to be the case on a certain issue. This is the wrong approach, even if your views happen to be ones which would emerge from sound reasoning. One skill we hope you will develop through your study in the Reason and Argument component is to be able to defend your beliefs. To repeat, then, it is no good when answering a question on an AT just to report on your own unchallenged beliefs. You must justify any position you adopt with an appropriate argument.