The answer is, b. va a comprar
1. Vive
2. Estudian
3. Fue
4. Respeten
5. Publica
6. Lucha
7. Resuelva
8. Preocupa
It might have been really hard for her because some words in Spanish don't mean the same thing in English so you have to find a similar word so it makes sense. So I think that was her problem.
Also, this is what I could understand from the question... Hope this helps you!!