Combo boxes - default option or message

When I'm using a Combo Box on a form (i.e. a drop down menu), is there a way of setting one of the options as the default?

I want the user to suggest from three options (say, Option 1, Option 2, and Option 3), and when the form first initializes I would like the option selected to automaticelly be Option 1 (which the user can then change if they wish). Thank you!