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

在20年前保卫祖国的战斗中，他失去了一条手臂。但是他却凭着钢铁般的意志，战胜了伤残，战胜了自我，刻苦学习，奋力拼搏，成为新时期一名优秀的军事人才。他就是被人们誉为“独臂英雄”的（）。