Grammar challenge for B1 level
All of these are grammatically correct. The first and fourth one made me pause, but they are solid, if not the best choices.
Sentences like the following are commonly spoken:
Question: "Did you run yet?"
Answer: "Yes I ran an hour ago."
Even the odd sounding first sentence is correct.
"You finished painting the bathroom"
is certainly grammatical. Putting a question mark at the end cannot change its correctness:
"You finished painting the bathroom?"
The question mark merely changes the tone in which it should be read. Adding "yet" to the end doesn't destroy this correctness. People do talk this way.
Your question is good, but you might ask for the "best" or "most natural" answer rather than the "correct" one.