So why wouldn't "Hva gjor du selger" work here?
Norwegian doesn't have the 'do'-construction, so to ask questions you put the verb at the front, right after the question word. 'do' would translate to 'gjør' in other sentences, however. "Do it!" = "Gjør det!".
Why is every answer i choose wrong? So i can't finish the lesson
For multiple choice tasks, you're asked to pick all the correct answers.
In this case, that would be "What do you sell?" and "What are you selling?".
why is it wrong to say 'Hva selger deg'? I thought that 'you' on the end of the sentence is a deg rather than du