请教PREP第一套的162题

162.
                (33659-!-item-!-188;#058&007012)

The government predicts that, for consumers and businesses that make a large number of long-distance calls, the Federal Communications Commission's recent telephone rate cuts will greatly reduce costs, though some consumer groups disagree with the government's estimates, suggesting they are too optimistic.

(A) The government predicts that, for consumers and businesses that make a large number of long-distance calls, the Federal Communications Commission's recent telephone rate cuts will greatly reduce costs

(B) The government predicts that costs will be greatly reduced for consumers and businesses that make a large number of long-distance calls by the Federal Communications Commission's recent telephone rate cuts

(C) The government's prediction is, for consumers and businesses making a large number of long-distance calls, costs will be greatly reduced by the recent telephone rate cuts made by the Federal Communications Commission

(D) For consumers and businesses that make a large number of long-distance calls, the government's prediction that the Federal Communications Commission's recent telephone rate cuts will greatly reduce costs

(E) For consumers and businesses making a large number of long-distance calls, the government predicts that the recent telephone rate cuts that the Federal Communications Commission has made will greatly reduce costs

答案是A, 我怎么也不明白？我觉得B也没有错呀。是不是主动语态优于被动语态？

请高人指点！谢谢

B中by介词短语修饰对象不清.

不懂

by...不就是动作的发出者嘛？为什么修饰对象不清？我怎么觉得B比A表达得还要清楚些呢。选A还是因为主动优于被动？

求高人指点~