If you are referring to columns then what is stored in a combo box are the fields for whatever the query or record source of the combo box.
In your question you have ID, Name, A1 ... A5. If your table has 100 records then the combo box will have 100 rows from that table.
If you are able to select ID, Name, A1, A2 or A3, etc. as individual selections, in other words the drop down box displays the ID, Name, A1, etc. on a separate line then...