You need to loop through the array to check which has been selected, or you can store the index when it is being selected.
VB Code:
'Loop through the items.
Dim iSelectedIndex As Integer
For iSelectedIndex = 0 To Option1.UBound
If Option1(iSelectedIndex).Value = True Then
'Found the one that is selected, exit the loop
Exit For
End If
Next
MsgBox "Selected item has index " & uSelectedIndex
VB Code:
'Storing the item when it is being selected
Private iSelectedItem As Integer
Private Sub Option1_Click(Index As Integer)
iSelectedItem = Index
End Sub