Having received ______ training of the TCL. Company, he was offered ______ important position in

management.[ ]

A. the; an        

B. /; an            

C. the; /          

D. a; a

函数f（x）=（x+1）（x²-x+1）的导数是（　　）

A．x²-x+1

B．（x+1）（2x-1）

C．3x²

D．3x²+1