Contract closure procedure and administrative closure procedure have several common characteristics, the following are their common characteristics except______.

A) exit criteria
B) contract term
C) step-by-step
D) activities and responsibilities

经国务院批准，中国银行、中国建设银行、中国工商银行改制为股份制银行。一些国有商业银行改制为股份制银行，主要是改变了（    ）

A．公有制的经济性质

B．公有制的实现形式

C．公有制的地位

D．公有制的物质基础