She has been in ( ) doctors describe as a vegetative state f

答案是A.
理由如下：整句的结构是：she has been in a state.what作in的宾语,同时做describe的宾语.固定搭配：describe ..as..
楼上选c是不正确的,因为that引导宾语从句在句中不做任何成分,而此句describe后面很明显缺少宾语.
附：what从句比较特殊,既可以看做定语从句,同时可以看做是宾语从句,因为what本身相当于：先行词+关系代词.
此句有点难度,建议多了解what相关的语法.
最后,祝你英语水平越来越好!