What are your plans for the future?
Dropout - You don't have, and you don't plan on getting your highschool degree.
Workplace - You have / will have a highschool degree, and plan on going right into the workforce.
College / Trade School - It's called different things, but you basically get a diploma, and go into a trade. (Y'know, like those commercials you see on television? Teachers Assistant, Medical Office Technician, 3D Animation etc..) It's also called a 'Career College'
University - You have / will have an undergraduate (bachelors) degree of some sort.
Grad School - You have/will receive a graduate degree (doctorate).
This is just for your goals or what you have already. So for example, if you don't even have highschool yet, but you plan to go to University, then choose University, not Highschool.