I had the following question "Estan vds. de pie o sentados"
I know the answer is "Nosotros estamos de pie"
But, I am a little confused with the question - Estan means they are or are they. So I understand that the question is "are they standing or sitting."
What is confusing me is why Vds. is in the sentence? Vd. meaning you, & Vds. being the plural of you. What does it add to the question?