一道GWD的题
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.
- heavily accounts for almost half of the $20.8 billion increase in drug spending last year, the remainder of which came[C1]
- heavily were what accounted for almost half of the $20.8 billion increase in drug spending last year; the remainder of the increase coming[C2]
- heavily accounted for almost half of the $20.8 billion increase in drug spending last year, the remainder of the increase coming [C3]
- heavily, accounting for almost half of the $20.8 billion increase in drug spending last year, while the remainder of the increase came[C4]
- heavily, which accounted for almost half of the $20.8 billion increase in drug spending last year, with the remainder of it coming
我想问下错误的A选项中，the remainder of which came from sales of the 9,850 prescription medicines that companies did not advertise or advertised very little.算是一个独立的main clause么？还是从句？看见WHICH，我有点恍惚~
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