单击一次命令按钮之后，窗体中的输出结果为______ 。 Private Sub Command1_ Click()Dim a As SingleDim b As Singlea = 10b = 20Call Num(a, b)Print a, b End Sub Sub Num(a, b)t = aa = b / tb = t End Sub

A．20 10

B．10 20

C．2 10

D．10 10