A:can’t have said
B:might not have said
C:couldn’t say
D:mustn’t have said
现有电源、开关、电流表、电压表、灯泡、滑动变阻器各一个,其中灯泡的U﹣I图象如图所示.将这些元件用导线连成电路后,闭合开关,滑动变阻器的滑片从最左端向右滑动的过程中,电压表的示数从5V开始减小,电流表的示数从0.3A开始增大.下列结论正确的是( )
—Did you know China is one of the oldest countries in the world?
—Yes, I did. It’s ______ than the US.
—OK, thank you.