Well, my son (told me although he likes the Games very much he doesn't consider them heroes, so he left the question blank. Well he did this for 2 out of the 10 questions, and scored an 80.
First, DD11 can take a week to decide her own opinion on things like this - so I have told her that 1) her teacher doesn't have the right to her innermost thoughts and feelings, and 2) all she needs to do is put down any defensible answer and defend it. This has helped quite a bit on opinion questions.
Second, talking about grades and the future has backfired for us - so we keep it concrete and immediate. She must complete any assignment she brings home; no leaving half of the questions blank! Until it's done, there just isn't time for other things she would like to spend her time on. The school has dangled advanced math for next year in front of her as a carrot, and she has a personal goal of getting into it, so she puts effort into math so that she can meet those requirements. Sometimes I do have to remind her that she has her own reasons for doing the extra math (which she still doesn't find interesting), but it's her choice whether she wants the reward next year - I don't care.
DD does not like seeing truly wretched work with her name on it, so if she does the work, it's usually good enough for the teacher. I stay out of any quality discussion. The more I get involved, the more she just refuses to do the work - and we had enough of that in elementary school.
On the other hand, I'm perfectly content for her to get Bs in middle school. I see this as a time for her to act independently and see the consequences with minimal risk, so she will be self-motivated to get the higher grades in high school when it matters. If your philosophy or situation is different, your response will be also.
