From 1978 to 1988, beverage containers accounted for a 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 recycled 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.

答案选C 虽然觉得其他都选项不对，但就是想不出C为什么对。
已经搜索过以前的解释，就是想不通。
今天脑子有点搭牢了。。。求指教。