For i = 2 To Cells(Rows.Count, 1).End(3).Row
x = Cells(i, 2)
Select Case x
Case Is < 60
Cells(i, 3) = "F"
Cells(i, 4) = WorksheetFunction.Rank(Cells(i, 2), Range(Cells(2, 2), Cells(Cells(Rows.Count, 1).End(3).Row, 2)))
Case Is < 70
Cells(i, 3) = "D"
Cells(i, 4) = WorksheetFunction.Rank(Cells(i, 2), Range(Cells(2, 2), Cells(Cells(Rows.Count, 1).End(3).Row, 2)))
Case Is < 80
Cells(i, 3) = "C"
Cells(i, 4) = WorksheetFunction.Rank(Cells(i, 2), Range(Cells(2, 2), Cells(Cells(Rows.Count, 1).End(3).Row, 2)))
Case Is < 90
Cells(i, 3) = "B"
Cells(i, 4) = WorksheetFunction.Rank(Cells(i, 2), Range(Cells(2, 2), Cells(Cells(Rows.Count, 1).End(3).Row, 2)))
Case Else
Cells(i, 3) = "A"
Cells(i, 4) = WorksheetFunction.Rank(Cells(i, 2), Range(Cells(2, 2), Cells(Cells(Rows.Count, 1).End(3).Row, 2)))
End Select
Next
End Sub