The meaning of the sentence is that everybody there did it
if I have any mistak, please correct me
In case the sentence were "... Done at peter's house"
what should be the answer
once again if I have a mistake feel free to correct me
This is one for the professionals...Its all about context.
Where the meaning is that everyone has completed a task then
is best suited
suggests it may be in response to a question that some were not completed
Hope this helps