Which of the following translations fall into the category of grammatical errors？

A.跟他结婚后，她的麻烦开始了。After marrying him， her trouble began.

B.拥挤的交通 crowded traffic

C.掌上明珠 the pearl on one’s hand

D.促进和平统一事业 promoting the cause of peaceful unification

正确答案：跟他结婚后，她的麻烦开始了。After marrying him， her trouble began.