Critical Reasoning

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.


What would be the answer?I fail to undersatnd B being the right answer....

B. So far only the best, most experienced drivers for Partorian trucking companies have been driving triple-trailer trucks .
Accidents are not taking place because of the most exp drivers.
If we increase the number of triple-trailer trucks, we will require exp. drivers as well.
And if we are not having exp drivers then triple-trailer trucks cant do anything itself to avoid accidents so all depends upon exp drivers not on
triple-trailer trucks.

Ankur's reasoning is perfect.

Basically, what B says is triple-trailer trucks were not themselves the reason for the low number of accidents, but rather the reason was strong experience of the drivers of these trucks. So, the whole point of increasing more such trucks becomes irrelevant!

Ankur87 and The Iceman have nailed it.

From cause and effect perspective, the conclusion states:
Cause: Increase usage of triple trailer trucks -> Effect: Reduced highway deaths

To weaken the conclusion, we need to show that its not the triple trailer trucks that would reduce the deaths, instead the reason / cause is something else. Answer choice B provides this reason (its the not the trucks but the exp drivers that would help in reducing deaths)