某VB程序的事件过程代码如下:
Private Sub Command1_Click()
Dim a As Integer
Dim s As String
s = "data:"
a =" Int(Rnd" * 90)
s =" s" + a
Text1.Text = Str(a)
End Sub
程序运行后,单击命令按钮Command1,弹出如第8题图所示的错误提示信息,产生此错误的语句是( )

A.s = "data:" |
B.a =" Int(Rnd" * 90) |
C.s =" s" + a |
D.Text1.Text = Str(a) |