分析以下Visual Basic程序，其运行结果为______。
Private Sub Form_Click______
score = Int(Rnd*10)＋80
Select Case score
Case Is＜60
A$ =“F”
Case 60 To 69
A$ =“D”
Case 70 T079
A$ =“C”
Case 80 T089
A$ =“B”
Case Else
A$ =“A”
End Select
Print A
End Sub