From 1978 to 1988, beverage containers accounted for steadily decreasing percentage of the total weight of household garbage in the United States. The increasingly widespread practice of recycling aluminum and glass was responsible for most of this decline. However, although aluminum recycling was more widely practiced in this period than glass recycling, it was found that the weight of glass bottles in household garbage declined by a greater percentage than the weight of aluminum cans.
Which of the following, if true of the United States in the period 1978 to 1988, most helps to account for the finding?
A Glass bottles are significantly heavier than aluminum cans of comparable size.
B Recycled aluminum cans were almost all beverage containers, but a significant fraction of the reclycled glass bottles had contained products other than beverages.
C Manufacturers replaced many glass bottles, but few aluminum cans, with plastic containers.
D The total weight of glass bottles purchased by households increased at a slightly faster rate than the total weight of aluminum cans.
E In many areas, glass bottles had to be sorted by color of the glass before being recycled, whereas aluminum cans required no sorting.
这个题目答案是C 我选的A 怎么就是想不明白啊··· 希望大家帮我解答一下 谢谢啦！ | 
