How to file W-9 form for a school contest?

My school had contest for graduating cap decoration and I won. I received an email with a W-9 form to fill out in order to obtain my cash price. I was completing the form until I ran into the Line 3  - " Check the appropriate box for federal tax classification" However, I am not sure what option to mark as the options given are only for business (I do not have a business). Unfortunately, I cannot leave that section blank.