在窗体上画一个名称为Command1的命令按钮, 一个名称为Label1、 Label2、Label3的标签, 然后编写如下的事件过程:Private x As IntegerPrivate Sub Command1_Click()Static y As IntegerDim z As Integern = 10z = n + zy = y + zx = x + zLabel1.Caption = xLabel2.Caption = yLabel3.Caption = zEnd Sub运行程序后, 连续三次单击命令按钮后, 则三个标签中显示的内容分别是
A.10 10 10
B.30 30 30
C.30 30 10
D.10 30