.Li Yuchun’s song was a______ at once and its recording tape rose to No.1 on the best seller list.

A．shock

B．strike

C．hit

D．beat

下列程序的执行结果为()。　　a=10　　b=20　　If a ＜ ＞ b Then a=a + b Else b=b-a　　Print a，b

A． 20 20

B． 30 20

C． 30 40

D． 15 15