"Why are you under the desk?"

Translation: Γιατί είσαι κάτω από το γραφείο;

[Moritz7698]

I had to pick from 3 greek options of which two were exactly the same except for one using "είσαι" and the other "είσαστε". I admit it is unlikely to have multiple people under the desk, but why is the second option wrong?

[milliByteG]

What if είναι is used? How are we to know who the subject is?

[Glossmad]

I wonder why I was marked wrong for: γιατί είσαι εσύ κάτω άπο το γραφείο

[StanGuthrie]

I saw this option two times... the response options should be reviewed to remove duplicates.