Making a Histogram (Grade Distribution)

Attachment 14131

In the file above, I need to make a histogram with this basic code:

Dim MyStat As Chart
Set MyStat = ActiveSheet.Shapes.AddChart.Chart
With MyStat
.SetSourceData Source:=Sheets("Sheet2").Range("B1:B5")
End With

In user form C_Grade_Distribution, I need to make a histogram for an option from a combobox: certain grade or the sum of grades (general grade).

Thanks