Mary got caught cheating on her final exam, but her professor didn't expel her. She was relieved _______________ off the hook. A. having let B. having been let C. to have let D. to have been let

Mary got caught cheating on her final exam, but her professor didn't expel her. She was relieved _______________ off the hook.

A. having let

B. having been let

C. to have let

D. to have been let

`->` Cấu trúc : S + have/has been +  $V_ed$/$P_2$+ … + by O.

 `->`Tạm dịch : Mary bị bắt quả tang gian lận trong kỳ thi cuối kỳ, nhưng giáo sư của cô ấy không đuổi học cô ấy. Cô cảm thấy nhẹ nhõm khi được thả  ra khỏi móc.