A.若甲表是电压表,乙表是电流表,则电阻R1、R2并联 B.若甲表是电流表,乙表是电流表,则电阻R1、R2串联 C.若甲表是电压表,乙表是电压表,则电阻R1、R2串联 D.若甲表是电流表,乙表是电压表,则电阻R1、R2并联