I think you can't hear very well the difference between ji and je ni and ně on the recordings and this is confusing, I understand that this is spoken and not classroom language but in the real life you have a context. And here there were two recordings, and I kept listening to them a few times, that I don't think make it possible to say what is there.
You're on the right track. You only need the question word to match in the grammatical case.
Ona hledá doktora. = She is looking for a doctor. In a declarative sentence, the doctor is in the accusative.
Twisting the sentence into a question, you're asking about the object, so the question word needs to be in the accusative. Who is she looking for? = Koho (ona) hledá?
Great and always perfect, your answers Jamie. In my notes, I already wrote kdo when "who" refers to the subject/nominative; koho when "who" refers to the object/accusative. Now referring to "She (Jana) is looking for the doctor" 1. Kdo doktora hledá? Answer: JANA hledá doktora/doktorku 2. Koho Jana (ona) hledá? Jana DOKTORA/DOKTORKU hledá. [2.Who is she/Jana looking for? Jana is looking for the doctor]. I hope not being mistaken so that I can take notes again, to learn to practice :-)
Everything is correct Lucia :-), however, there is one thing that you'll hardly learn on Duolingo. The sentences here are without context, which allows the word order to be really flexible. Once you have the context, you are bound to emphasize certain words and therefore you have to be more careful so the whole message you present sounds natural.
I might have written it somewhere already, but I'll write it here again.
The second position in a sentence is for clitics.
The first and the last position in a sentence is emphasized.
The first position connects the sentence with the previous one and the last position in a sentence brings a new information.
The difficult part is of all the words in a sentence to identify what should be emphasized.
Going back to your sentences...
- Kdo hledá doktora? - this is a standard, neutral question; usually when you're looking for something, important and new is the thing or person you're looking for (so it will be the last element)
For the answer, the doctor is still important -> it will be emphasized; but it's no longer new, so you'll start the sentence with it - Doktora hledá Jana. - This time "Jana" is the new important information as it's the person who is seeking someone.
- Who is Jana looking for? - Koho hledá Jana? / Koho Jana hledá? - Jana is looking for a doctor. Jana hledá doktora/doktorku. Same as above, you're connecting the two sentences together.
I don't want this post to be too long, but I hope it makes some sense.
Just one more example: When are we going to Prague? Kdy pojedeme do Prahy? - 1) V červnu pojedeme do Prahy. 2) Pojedeme do Prahy v červnu. 3) Do Prahy pojedeme v červnu. 4) Pojedeme v červnu do Prahy. 5) Do Prahy v červnu pojedeme.
Of the five grammatically correct sentences, only one fits in this context. The question is - which one. :-P
Oh, I hope it was not so difficult and confusing. But yes, the sentence 3 is correct! :-) You're asking "kdy - when", so in the answer the time (in June) has to be the most important & new information.
For the record, you could also answer shortly "In June. - V červnu." instead of saying the whole sentence "Do Prahy pojedeme v červnu."