设A , B , C均为n阶方阵,
,
,则
的值为( )。\n \n \n \n \n \n \n
\n \n \n
\n \n \n
\n \n \n 
,
,则
的值为( )。\n \n \n \n \n \n \n \n \n \n \n A.\n
\n \n \n \n \n \n \n B.\n
\n \n \n \n \n \n \n C.\n
\n \n \n \n \n \n \n D.\n
