Giving up my job to go back to full-time education was a big but now I know it was the b

问题补充：

Giving up my job to go back to full-time education was a big , but now I know it was the best decision I ever made.

A. project

B. commitment

C. competition

D. ambition

答案：

A. project

(答案→)B. commitment

C. competition

D. ambition

解析：考查名词辨析。根据句子的“现在我知道这是最好的决定”，可知，放弃工作重新参加全职教育是一个很大的投入。故答案选B.