问题如下：
Monetarists favor a limited role for the government because they argue:
选项：
A.government policies operate with a lag.
B.firms take time to adjust to systemic shocks to the economy.
C.resource use is efficient with marginal revenue and cost equal.
解释：
A is correct.
Monetarists caution policy effects can occur long after the need for which they were implemented is no longer an issue.
考点：Monetarists
解析：因为政府制定的政策存在时滞，可能等到政策开始起效时候，经济已经自行恢复了，所以货币学派不建议政府扮演干预经济的角色。A选项正确。
本题考察的主体是政府，不是企业，所以C选项不入选。
C为什么不对呢？为啥说是政府不是企业？政府、企业傻傻分不清，感觉C没问题呀
