FR: Is that on the ground floor?

[Ayline]

I am doing Pimsleur and the question is "is that on the ground floor?" referring to "le bureau" and the translation is given as "est-ce que c'est au rez-de-chaussee?". Now we are asking about a definitive thing but it still translates as "c'est".
So my understanding is because "le bureau" is not mentioned within the sentence it is "c'est" or it would be "le bureau,est-ce qu'il au rez de chaussee?"Is my thinking correct?
Would it be OK to say "est-ce qu'il au rez de chaussee?", if "le bureau" was mentioned in the previous sentence?

Merci.

 

[Maître Capello]

To translate "Is that on the ground floor?", I'd say Est-ce que c'est au rez-de-chaussée ?

But if the meaning is rather "Is it on the ground floor?", referring to a particular office mentioned earlier, I'd say Est-ce qu'il est au rez-de-chaussée ? (By the way, please don't forget the verb est, which is required.)