单项选择题

在窗体上画一个命令按钮(其NAME属性为Command1),然后编写如下代码:  Option Base 1  Private Sub Command1_Click()   Dim a   s = 0   a = Array(1,2,3,4);j = 1   For i = 4 To 1 Step -1    s = s + a(i) * j    j = j * 10   Next i   Print s  End Sub  运行上面的程序,单击命令按钮,其输出结果是

A.4321
B.1234
C.34
D.12