下列围绕采购供应商选择的做法中，（）是不恰当的

A、采购部门根据历年供应商的供货情况建立了一个供应商数据库，根据数据库选择合格供应商 

B、首先进行供应商调查，满足标准要求后可纳入合格供应商名单 

C、为保持采购的公开透明，采购均采取招标形式选择合格供应商 

D、把采购物品分为3个等级，最低一级供应企业可以没通过ISO9001认证

Which of the following policy tools is the least likely to be available to the U. S. Federal Reserve Board（）

A. Setting the discount rate at which banks can borrow from the Federal Reserve.

B. Requiring the banking system to tighten or loosen its credit policies.

C. Increasing or decreasing bank reserve requirements.