请教的PREP SC

 To meet the rapidly rising market demand for fish and seafood, suppliers are growing fish twice as fast as their natural growth rate, cutting their feed allotment by nearly half and raising them on special diets.

C D

(A) their natural growth rate, cutting their feed allotment

(B) their natural growth rate, their feed allotment cut

(C) growing them naturally, cutting their feed allotment

(D) they grow naturally, cutting their feed allotment

(E) they grow naturally, with their feed allotment cut

选项里面的grow不用平行的，第一个growing才是和后面平行的那个动词，选项里面的they grow naturally,意思就是他们自然生长的速度，如果选C就变成了growing fish twice as fast as growing them naturally,看起来很对称，但是逻辑意思上就不对了，how can yo GROW sth Naturally? 只有sth grow naturally的说法

C的逻辑意思就是错得，只有D对。