If one of Jean's credit cards charges more than 2 percent

Thanks MacFauz, I thought so, on the same line. Since the source was princeton review, I gave princeton review the benefit of doubt and I reached this predicament.
But MacFauz, I beg to disagree with you on your statement:" it would make more sense and the answer to which is < 900". I think if the question was to find the maximum possible balance, it should have been any value just below 892.50$ and that would be C which is 892$.
The detailed calculation would be: Balance*Interest<17.85 where Interest > 2% and so putting 2% to find the baseline of B, we get B<829.50$. And from the main equation: Balance<1785/interest, when interest increases more, the max possible value for balance dips further.