下面程序运行后的结果是( )。 Private Sub Form_Click()Dim s As Integer，k As Integer,i As Integer，n As Integers=1fori=1 to 3 forj=i to 3 for k=j to istep-1 s=s*knextk,J,iprint s End Sub

A．6

B．72

C．144

D．432