单选题 阅读程序：
Option Base 1
Sub P(b() As Integer)
For i=1 To 4
b(i)=2*i
Next i
End Sub
Private Sub Form_Click()
Dim a(4)As Integer
For i=1 To 4
a(i)=i+4
Next i
P a
For i=1 To 4
Print a(i)
Next i
End Sub
运行上面的程序，单击窗体，输出结果为______。