在思维创新过程的有关研究中，沃拉斯所提出的思维创新过程分为（）阶段。

A.准备期

B.酝酿期

C.豁朗期

D.验证期

The crowding-out model implies that a:（）

A. budget deficit will increase the real interest rate and thereby retard private investment.

B. budget surplus will retard aggregate demand and trigger an economic downturn.

C. budget surplus will be a highly effective weapon against inflation.