The problem, which is complicated, has been solved.

The problem, which is complicated, has been solved.
A、这个问题是复杂但是可以解决了。
B、这个很复杂的问题可以被解决。
C、这个问题是很复杂的但是被已经解决了。
D、这个很复杂的问题已经解决了。
【正确答案】：D
【题目解析】：p99