oracle关闭数据字典访问权限需要执行的命令为:()
A.alter system set O7_DICTIONARY_ACCESSIBILITY=0 scope=spfile; B.alter system set O7_DICTIONARY_ACCESSIBILITY=FALSE scope=spfile; C.alter system set O7_DICTIONARY_ACCESSIBILITY=null scope=spfile; D.alter system set O7_DICTIONARY_ACCESSIBILITY=none scope=spfile;