小弟覺得答案B比較OK
在答案B中
Expanding its production of regenerators will require Light-line to spend proportionately more on labor and materials.
在比例上花在勞工和物料的費用增加了, 有可能那個比例的增加反而使得公司沒辦法賺錢
在答案E中
Several manufacturers are developing regenerator technologies that will allow signals to be transmitted many times farther than at present before requiring regeneration.
Several manufacturers 沒有說明有沒有包含Light-Line公司, 而且這樣的科技還沒被發展出來而題目是說 if new long-distance fiber-optic telecommunications networks are constructed.
現在就要建設好像不跟未來才會發生的事情產生關聯
可以在討論看看