"Are you at home?"
I know the multiple-choice options are randomized, so you may not have gotten exactly the same ones, but in my case one of the options was "Siz evde mısınız?"...which (I think) was wrong because it used the undotted i. Maybe you got the same sentence and didn't notice the missing dots?
That's "are you at your home" which admittedly is very similar. "Evinde" is possessive. The sentence in this lesson allows for the possibility that you are at someone else's home.
For example, if a friend is staying with me but I am at work, I could ask "evde misin" to ask if they are at my (temporarily shared) home.
Hope that helps!