Checkbox Can I do This

I have a userform that contains 15 labels, each label has Numbers in it each time i click on a label the text is inserted into an excel spreadsheet. I use it as a fast input solution and works well and has done for a few years.

I Now want to Add three checkboxes to the userform
If checkbox One is ticked i want the letter "A" and the number in the label i choose to be inserted into the spreadsheet.
Checkbox Two "B"
Checkbox Three "c"

I would only ever tick one of the checkboxes never two or three so it would be A, B or C

This is the code for The Labels i use

private Sub Label4_Click()
Call InsertTextSelection(Label4.Caption, RGB(0, 0, 255), 0)
End Sub

Private Sub Label5_Click()
Call InsertTextSelection(Label5.Caption, RGB(0, 0, 0), 0)
End Sub

and so on

This is the Call Insert textselection

Public Sub InsertTextSelection(text, colour, hours)
    UserForm1.Hide
    r = Selection.Row
    c = Selection.Column
    Range(Cells(r, c - 0), Cells(r, c - 0)).Select
    With Selection
        .ClearContents
        .Font.Size = 9
        .Font.Color = colour
        .MergeCells = True
        .HorizontalAlignment = xlCenter
        .VerticalAlignment = xlCenter
        .Value = text
    End With
    
    End Sub

The userform works by doubleclick

Hope you Can help

Dave