______ are the four major activities of software configuration management.
①configuration identification ②statement report ③change control
④preparation of requirement document ⑤configuration auditing

A．①②③④

B．①②④⑤

C．①②③⑤

D．②③④⑤

转8AG、转8G、转K1、转K2型弹性下旁承磨耗板上平面与滚子距离有何规定？不符时如何调整？