The answer is (usted) because you dont have a personal relationship with this person.
ustedes means you guys
vosotros means all of us
tu is used for someone whom you are close with like a family member or someone whom you have know for a while.
Answer:
1. Americano/a
2. Español/a
3. Hondureño/a
4. Chileña/o
5. Venezolanos.
Explanation:
I don't know 6-9 because I think those require a word bank