[求助]XDF小蓝149

In the nation artoria,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 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.Partoria trucking companies have so far used triple-trailer trucks on lightly traveled sectio of major highways only.

C.Very few fatal collissions involving trucks in Partoria are collissions  between two trucks.

答案给的是A,可A什么意思啊，怎么就削弱了呢？我选的是C，我觉得更有可能啊，很少有事故涉及到两卡车，那就换任何

trailer也没用啊，有可能是其他车型所造成的，而非truck,希望高手们能解决一下，谢谢。

A的解释 是 那种TRUCKS事故少 只是因为用的少 不是因为安全 ，所以weaken

C选项属于无关选项，和事故发生的种类无关，只和数量有关