请教呀~~很是头疼这个题~~

狂威雪

In the nation of Partoria, large trucks currently account for 6 percent of miles driven on Partoria’s roads but are involved in 12 percent of all highway fatalities.  The very largest trucks—those with three trailers—had less than a third of the accident rate of single- and double-trailer trucks.  Clearly, therefore, one way for Partoria to reduce highway deaths would be to require shippers to increase their use of triple-trailer trucks.

Which of the following, if true, most seriously weakens the argument?
A. No matter what changes Partoria makes in the regulation of trucking, it will have to keep some smaller roads off-limits to all large trucks.
B. So far only the best, most experienced drivers for Partorian trucking companies have been driving triple-trailer trucks.
C. Very few fatal collisions involving trucks in Partoria are collisions between two trucks.
D. In Partoria, the safety record of the trucking industry as a whole has improved slightly over the past ten years.
E. In Partoria, the maximum legal payload of a triple-trailer truck is less than three times the maximum legal payload of the largest of the single-trailer trucks.
答案是B，但是我不明白它的削弱方式，出题者的出题思维，它的因果关系怎样？

狂威雪

恩，好开心了，终于明白了这个题隐含的意思。每次看做错的题，总是看不出来里面的隐含的意思，请问怎么训练的呀？