求大神帮忙看一下SCprep08一道语法题

Many financial expertsbelieve that policy makers at the Federal Reserve, now viewing the economyas balanced between moderate growth and low inflation, are almost certainto leave interest rates unchanged for the foreseeable future.

A.     Reserve, now viewing the economy as balanced between moderate growth andlow inflation, are

B.     Reserve, now viewing the economy to be balanced between that of moderategrowth and low inflation and are

C.     Reserve who, nowviewing the economy as balanced between moderate growth and low inflation, are

D.     Reserve, who now viewthe economy to be balanced between that of moderate growth and low inflation,will be     (A)

E.     Reserve, which now views the economy to be balanced between moderategrowth and low inflation, is

此题C选项为什么错误？

答案说：

C. policy makers缺谓语动词；who做限定性修饰使得语义上不合理。

但是policy makers不是有谓语动词are吗？是不是因为这个选项 非限制性定语从句who的逗号位置错误才错的？