运行下列程序:Dim x, yPrivate Sub Form_Click( )x = 1: y = 1: z = 1fun1 (1)Print x; y; zE

运行下列程序：

Dim x, y

Private Sub Form_Click( )

x = 1: y = 1: z = 1

fun1 (1)

Print x; y; z

End Sub

Private Sub fun1(a)

x = a + x: y = a + x: z = a + y

End Sub

单击窗体后，则输出结果是( )。

A.1 1 1

B.2 3 1

C.2 3 4

D.2 2 1