请教PREP1中第106题。谢谢！

106.
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Officials at the United States Mint believe that the Sacagawea dollar coin will be used more as a substitute for four quarters rather than for the dollar bill because its weight, only 8.1 grams, is far less than four quarters, which weigh 5.67 grams each.

(A) more as a substitute for four quarters rather than for the dollar bill because its weight, only 8.1 grams, is far less than

(B) more as a substitute for four quarters than the dollar bill because it weighs only 8.1 grams, far lighter than

(C) as a substitute for four quarters more than for the dollar bill because it weighs only 8.1 grams, far less than

(D) as a substitute for four quarters more than the dollar bill because its weight of only 8.1 grams is far lighter than it is for

(E) as a substitute more for four quarters rather than for the dollar bill because its weight, only 8.1 grams, is far less than it is for

答案选的C，但是less可以修饰重量吗？不是应该用lighter吗？

这里是不是应该是修饰数字的不？

GMAC好像特别喜欢这种结构， 句子后面+ 形容词短语或者动名词短语...

less是修饰weigh的.句子主干是: it weighs less than four quarters.