if you're working, for example, for a firm like Betterware, the law still regards you as a 'sole trader'. (You're legally running your own business, even though you're acting as an agent for a major company). So it's the 'sole trader' section which you need to complete. (When you're asked for the name of your business, fill in your own name - not that of the company which is providing you with the work).
Chris



