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 Command1_Click()
Dim a As Integer,s As Integer
a = 8
s = 1
Do
s = s + a
a = a - 1
Loop While a<=0
Print s,a
End Sub
程序运行后,单击命令按钮,则窗体上显示的内容是

A.7 9
B.34 0
C.9
D.死循环