运行下列程序:Private Sub form_Click( )x$ = "123": y$ = "abc"n = Len

运行下列程序：

Private Sub form_Click( )

x$ = "123": y$ = "abc"

n = Len(x)

For i = 1 To n

Print Mid(x$, n + 1 - i, 1) + Mid(y$, i, 1);

Next i

Print

End Sub

单击窗体后，则输出结果是( )。

A.a1b2c3

B.a3b2c1

C.3a2b1c

D.1c2b3a