It is impossible to live in society and independent of society; and therefore it is difficult to      

society of      inequality as well as corruption.

A．remove; from

B．rid; of

C．substitute; with

D．simplify; by

观察下图，两汉时官员上朝可以坐着奏事，到宋朝时官员须站着奏事，明清时期大臣奏事必须跪着。官员上朝礼仪的变化说明古代中央政治制度演变的重要特点是（）

A．中央集权不断加强

B．皇权不断加强

C．封建等级制度不断强化

D．古代礼仪不断发展完善