OG67, so as to, 与they指代

67.         Congress is debating a bill requiring certain employers provide workers with unpaid leave so as to care for sick or newborn children.

(A) provide workers with unpaid leave so as to

(B) to provide workers with unpaid leave so as to

(C) provide workers with unpaid leave in order that they

(D) to provide workers with unpaid leave so that they can（D）

(E) provide workers with unpaid leave and

"they" in D语法上是没有指代的, 而B语法很合理.