[求助]Prep_SC90

90. The
parachutelike membranes of Africa’s
scaly-tailed flying squirrels differ from those of the flying squirrels in the
family Sciuridae because they are attached to a cartilage rod at the elbow
instead of the wrist.

A. because they
are attached to a cartilage rod at the elbow instead of

B. because of
being attached to a cartilage rod at the elbow rather than at

C. in their
attachment to a cartilage rod at the elbow instead of being attached at

D. in that they
are attached to a cartilage rod at the elbow rather than at

E. in their
being attached to a cartilage rod at the elbow instead of

A: instead of 应该补充完整at the wrist，否则会有歧义

B: because of + doing 不如从句表达清晰

C: 表原因用从句比介词强；instead of 前后不对称

D: correct

E: their being 错

请问这里的答案D中的they不存在指代不清吗？

我个人的看法，（1）也许会有，但从从句意上来说不会有，

（2）这题每个选项都有they，所以不必考虑