The problem __________, they went home.

The problem __________, they went home.
A、being solved
B、has been solved
C、been solved
D、has to be solved
【正确答案】：A
【题目解析】：考察独立主格，前面部分不是一个完整的句子，所以排除B、D项，The problem being solved=The problem solved，所以C项不选，选A。