语法求助 GWD 句子结构！

Scos

According to a recent study of consumer spending on prescription medications, increases in the sales of the 50 drugs that were advertised most heavily accounts for almost half of the $20.8 billion increase in drug spending last year, the remainder of which came from sales of the 9,850 prescription medicines that companies did not advertise or advertised very little.

A.heavily accounts for almost half of the $20.8 billion increase in drug spending last year, the remainder of which came
B.heavily were what accounted for almost half of the $20.8 billion increase in drug spending last year; the remainder of the increase coming
C.heavily accounted for almost half of the $20.8 billion increase in drug spending last year, the remainder of the increase coming
D.heavily, accounting for almost half of the $20.8 billion increase in drug spending last year, while the remainder of the increase came
E.heavily, which accounted for almost half of the $20.8 billion increase in drug spending last year, with the remainder of it coming

正确答案是 C

the remainder of the increase coming from sales of the 9,850 prescription medicines that companies did not advertise or advertised very little.
这句中coming的作用是什么呢？
我认为应该不是做increase的定语
如果是动词意义的话，为什么用现在分词形式呢
求大神指点

alzn2765

独立主格

Scos

alzn2765 发表于 2016-2-24 15:08
独立主格

一针见血  自己知识有漏洞
谢了！