Configuration management is the process of managing change in hardware，software，firmware，documentation，measurements，etc．As change requires an initial state and next state，the marking of significant states within a series of several changes becomes important．The identification of significant states within the revision history of a configuration item is the central purpose of （） identification.

A．baseline

B．value

C．cost

D．control

下述钡餐征象中，哪项与“胰头癌”无关（）

A.垫征

B.双边征

C.十二指肠圈扩大

D.笔杆征

E.反“3”字征