[求助]0308语法15劳烦各位赐教~~

totolin116

15．  In the years ahead, health professionals will be able to enhance or restore health far better _________ at present.

(A)
                whereas

(B)  they can

(C)
                than

(D)
                that are

这一题为什么不是  In the years ahead, health professionals will be able to enhance or restore health far better than they can at present.?

麻烦各位大虾赐教~~

yilin2288

完整的句子确实应该是than they can at present，   可是答案里没有这个选项，这里的they can 被省略掉了