[求助]GMATPREP的一道～困惑～语法题

Scientists believe that unlike the males of most species of moth, the male whistling moths of Nambung, Australia, call female moths to them by the use of acoustical signals, but not olfactory ones, and they attract their mates during the day, rather than at night.
a) by the use of acoustical signals, but not olfactory ones, and they attract
b) by the use of acoustical signals instead of using olfactory ones, and attracting
c) by using acoustical signals, not using olfactory ones, and by attracting
d) using acoustical signals, rather than olfactory ones, and attract
e) using acoustical signals, but not olfactory ones, and attracting

标准答案是d。
但我觉得d的前面还缺少一个by，否则句子结构不完整。大家觉得呢？

我做题时选的是c。

应该是D。

首先C在逻辑上也讲不通。

using ...已经表示方式了。

主要句子的结构是： the male.... , call female moth to them..., and attract ....