Select the word from the list that best fits the definition your parent’s friend a. tú b. usted c. ustedes

Probably choice b. usted.

tu is very informal, that would be like talking to your friend

ustedes is the plural form of usted so you wouldn't use that to refer to your parent's friend. 

I hope this helps you! :)

The answer would be B usted

The one that you got wrong was 6, it’s los lapizes