单片机复位后，SP、PC、I/O口的内容为（）

A..SP=07H      PC=00H        P0=P1=P2=P3=FFH
B..SP=00H      PC=0000H      P0=P1=P2=P3=00H
C..SP=07H      PC=0000H      P0=P1=P2=P3=FFH
D..SP=00H      PC=00H        P0=P1=P2=P3=00H