It really depends how you define 'hard' i.e. you could find the test really easy, but relative to past HSC papers you could find it to be the most difficult and thus give it a 10. So, are you asking about the difficulty of the test in general, or relative to past HSC papers?
^ To be honest, i freaked out when I saw the question, but realised that there was a much simpler way of finding the answer (I stared at it for a few minutes): substitute values into the equation! The answer (if i remember correctly) is A - Substituting in x=pi/2 (and the other values in the...