再问GWD逻辑

coffeeqoo

GWD6-Q32:
Proposal:  Carbon dioxide and methane in the atmosphere block the escape of heat into space.  So emission of these “greenhouse” gases contributes to global warming.  In order to reduce global warming, emission of greenhouse gases needs to be reduced.  Therefore, the methane now emitted from open landfills should instead be burned to produce electricity.
Objection:  The burning of methane generates carbon dioxide that is released into the atmosphere.
Which of the following, if true, most adequately counters the objection made to the proposal?

A.    Every time a human being or other mammal exhales, there is some carbon dioxide released into the air.
B.    The conversion of methane to electricity would occur at a considerable distance from the landfills.
C.    The methane that is used to generate electricity would generally be used as a substitute for a fuel that does not produce any greenhouse gases when burned.
D.    Methane in the atmosphere is more effective in blocking the escape of heat from the Earth than is carbon dioxide.
E.    The amount of methane emitted from the landfills could be reduced if the materials whose decomposition produces methane were not discarded, but recycled.
答案是C，但怎么感觉C是支持而不是反对啊？Methane更有效的话，温室效应更严重的呀，正好可以用Carbon dioxide替代~请牛牛们帮忙解答，看我是哪里理解错了

xn8510

奇怪，我也觉得C是错的：甲烷可以替代那些不产生温室气体的燃料，原来的燃料，不产生温室气体。甲烷代替传统燃料后，反而产生了温室气体。。。。这怎么可能呢？？？
但是，其它的四个选项似乎都是无关或“加强”选项：
A 每当人或动物呼吸时，都会产生二氧化碳——以此为由反对，很荒唐，无关；
B 甲烷转换为电，发生地距离垃圾堆很远——无论远近，都会产生二氧化碳，加重温室效应，加强；
D 在阻止热量脱离地球方面，甲烷比二氧化碳更有效——那么，燃烧甲烷，增加二氧化碳，进一步加重温室效应，加强；
E 如果产生甲烷的材料不被乱扔，而是被有效回收，那么，甲烷数量将会减少——明显无关

这么看来，似乎没有正确答案了。。。。还是我的理解有误呢？？同等高人来解答。。。。

mrj1104

D选项中，说甲烷比二氧化碳更有效地阻止热量进入大气，是不是就是说二氧化碳还比甲烷好些？

mrj1104

发个讨论稿你http://forum.chasedream.com/GMAT_CR/thread-352573-1-1.html?SearchText=GWD6 Q32

coffeeqoo

谢谢楼上！答案应该是D，proposal支持M发电，objection认为发电也会产生C，也是一种温室气体，而D说M产生温室效应的可能比C更大，也就是说发电产生C进入大气相比M没发电直接进入大气效果更差，所以还是发电好，反驳了Objection~不知道理没理解清楚~