单选题 下面程序运行时，单击窗体后，窗体上显示的结果是{{U}} {{/U}}。
Private Sub Form_Click
Dim I As Integer
Dim sum As Long
Dim t1 As Long
t1=1:sum=0
For 1=1 To 3
t1=t1*I
sum=sum+t1
Next I
Print sum
End Sub

• A.3
• B.9
• C.5
• D.6