单击命令按钮时，下列的执行结果是（ ）。 Private Sub Command1 Click（ ） Dim a As Integer，b As Integer，C As Integer a=2：b=4：c=6 Call S1(a．b) Print'a='；a；'b='；b；'c='；c Call S2(a，b) Print'a='；a；'b='；b；'c='；c； End Sub Private Sub S1(X．As Integer，Y As Integer) Dim C As Integer x=2*X：y=y+2：c=x+y End Sub Sub S2(x As Integer，ByVal Y As Integer) Dim e As Integer x=2*x：Y=Y+2：e=x+y End Sub