610.Rising inventories, when unaccompanied correspondingly by increases in sales,
can lead to production cutbacks that would hamper economic growth.
(A) when unaccompanied correspondingly by increases in sales, can lead
(B) when not accompanied by corresponding increases in sales, possibly leads
(C) when they were unaccompanied by corresponding sales increases, can lead
(D) if not accompanied by correspondingly increased sales, possibly leads
(E) if not accompanied by corresponding increases in sales, can lead

C为什么错呢？而且答案把时间状语改成条件状语不算错吗？谢谢

C. they were 可以省略不影响句意。

if 在这里比 when 更贴切一些。when 言外之意有别的时候，if 除了这种情况外没有别的可能性。 差别很难体会。

rising inventories .... increases in sales 对应