Gradually the road climbs among high mountains and through a dark forest ______ huge trees shut out the light with their thick towering leaves.
A、 whose
B、 what
C、 which
D、 that
【正确答案】：A
【题目解析】：该题考查的是关系分句。分句中的tress与先行项forest的关系为从属关系，表示所属关系时关系代词用whose，因此选A。