GWD22-Q18

Q18:

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.

1. heavily accounts for almost half of the $20.8 billion increase in drug spending last year, the remainder of which
                       came

2. heavily were what accounted for almost half of the $20.8 billion increase in drug spending last year; the remainder of the increase coming

3. heavily accounted for almost half of the $20.8 billion increase in drug spending last year, the remainder of the increase coming

4. heavily, accounting for almost half of the $20.8 billion increase in drug spending last year, while the remainder of the increase came

5. heavily, which accounted for almost half of the $20.8 billion increase in drug spending last year, with the remainder of it coming

   Answer: C

我的疑问是C当中accounted 和 coming 不是时态不一致不对称吗？

请NN指教