I'm studying japanese from not that long and a doubt came to my mind studying ある and いる verbs, so sorry in advance if the question isn't clear.
If we take those two phrases as example:
For what I've understood, in the phrase A, I want to underline the location of the desk, in this case the room. In the phrase B, instead, I want to underline that in the room there's a desk, so I give more importance to the object, not to the location.
If I would want to translate the phrase "there's a desk" without pointing out the location, I can choose between:
indifferently or, if my previous argument is correct, I have to choose C?