单项选择题

在窗体上画一个名称为Command1的命令按钮,然后编写如下事件过程: Private Sub subl(ByVal x As Integer, ByVal y As Integer, ByVal z As Integer) z=x*x+y*y End Sub Private Sub Command1_Click() Dim a As Integer a=8 Call subl(1, 2, a) Print a End Sub 程序运行后,单击命令按钮,则窗体下显示的内容是______。

A.8
B.2
C.5
D.11