C's are below average. (I think, it's been a while since I was in middle school) Motivating someone to get below average marks doesn't seem right. It'd be better to have a scaling reward that increases as the grade increases.
Yeah, a scaling system would be superior, but you have to understand that it's not the beginning of the year anymore. It's implausible for him to get higher than a C. Even a C is pushing it, I don't know if he can do it.
Either you guys clearly have no idea how a school system works or you've just been brought up by terrible, abusive parents.
Hey, bitch to him first
I gave an example of how I'm way better than him at school even though I do no homework, I didn't post my grades for no reason.