GRE Reading Comprehension: JiJing 352-GRE阅读机经352篇 - F9RBX65XLYKIS170J

Which of the following, if true, most seriously weaken the argument? A. Large amount of dust in the atmosphere would tend to keep heat from the Sun that reached the Earth's surface from escaping into outer space B. The glacial samples show that during the period between the two most recent ice ages the level of atmospheric dust was far lower than it was during either of ice ages C. Volcanic eruptions in the recent past have released sufficient dust to cause detectable changes in global temperature patterns D. The amount of dust in the atmosphere was significantly greater in the middle of the last ice age than at the end