✨ คำตอบที่ดีที่สุด ✨
問題文の後半に注目すると
she has to finish everything by herself in the situation
この英文の(in the situation)が(in which)になってsheの前に出た形(in which she has to finish everything by herself) が先行詞situationに続いて
She has found herself in a situation (in which she has to finish everything by herself). という問題文になっています
ありがとうございます