IT WASN’T AN AWFUL EXPERIENCE. IT WAS THE WORST THING _________HAS...

12. - 25 DE THI HOC KI 1 MON TIENG ANH LOP 12 CO DAP AN
25 DE THI HOC KI 1 MON TIENG ANH LOP 12 CO DAP AN

12. It wasn’t an awful experience. It was the worst thing _________has ever happened to me.

A. which

B. that

C. what

D. why