토익 문제 좀 갈쳐주세여ㅠ

1. The Enterprises' stock price is _____ 16 percent since the start of the year, mostly because of an increase in its overseas revenues.

behind, toward, up, around 중에 답이 up인데 이유를 모르겠어요ㅠ 다른것들은 왜 안되는건가요?