How can I report this using Event Tracking?

I have a form with a drop down (with 3 options in the drop down). Depending on whch drop down option the user selects, the form submits to 3 external websites (1 website for each of the 3 options). I need to track the number of times the form was submitted for option1, option2, option3.
Because I cant view the first page a user viewed when they left my website, the only way I can see is to gauge which option was selected and then the form submitted is by using event tracking. How can I set this up? I know that I can add an event to the Submit button, but I need to know which option was select too.