请教prep12 SC69

oskird

原题：
Laboratory rats and mice live up to 40percent longer than usual when fed a diet of at least 30 percent fewercalories than that which they would normally eat, but that otherwise containsall necessary vitamins and nutrients.

A.  ofat least 30 percent fewer calories than that which they would normally eat, butthat otherwise

B. with at least 30 percent fewer calories than what they would normallyeat though otherwise it

C. that has at least 30 percent fewer of the calories that they wouldnormally eat, but otherwise it

D. that has at least 30 percent fewer calories than they would normally eat but that otherwise

E. that has at least 30 percent fewer calories than that which they wouldnormally eat, though that otherwise

其他选项中的错误都看出来了，问题在D选项：
后句是与前句的diet进行比较，所以than they would normally eat中间是否少了个that，应为than that they would normally eat
希望有NN能回答！！