Using php/mysql.

I have a form to submit info to a table.

On the form I have a multiselect list box. Is it better to store a comma delimited string to one single field in the table once the form is submitted, or should I create a join table that has a separate row for each selected object in the list box?

What's the better option?

I am thinking I should create a join table, since each list item is linked to a table called "options".