OG11-50 请教

OG11-50

 If the county continues to collect residential trash at
current levels, landfills will soon be overflowing and
parkland will need to be used in order to create more
space. Charging each household a fee for each pound
of trash it puts out for collection will induce residents
to reduce the amount of trash they create; this charge
will therefore protect the remaining county parkland.

Which of the following is an assumption made in
drawing the conclusion above?
(A) Residents will reduce the amount of trash they
put out for collection by reducing the number
of products they buy.（居民通过减少购买产品的数量的方式来减少倒垃圾的数量，这样整体垃圾倾倒的数量会减少，这样垃圾填埋场就不会被填满，因此也就保护公用场地，为什么A不是假设呢？  ）
(B) The collection fee will not significantly affect
the purchasing power of most residents, even if
their households do not reduce the amount of
trash they put out. 与购买力无关
(C) The collection fee will not induce residents to （C的确可以作为假设，但是 A为什么不正确？）
dump their trash in the parklands illegally.
(D) The beauty of county parkland is an important
issue for most of the county’s residents.无关
(E) Landfills outside the county’s borders could be
used as dumping sites for the county’s trash. 无关

答案是C对，为什么A错呢

谢谢

我觉得这里问的是Which of the following is an assumption made in drawing the conclusion above

就相当于还要加一个additional premises 使得conclusion可以推出

那我觉得就相当于要加一个充分条件（这里不太清楚，也许错了，请指出）

这题的C属不属于lawyer说的排除他因

即排除charging a fee will induce residents to dump their trash illegally这种可能？？

不知道能不能这样理解？

逻辑一直不好 还请后来的xdjm多多指教