As a teacher/grammarian, I'd say B, as it follows the grammatical rules of inversion.
As an ordinary English speaker, however, I'd say 'None of these'. They are all extremely unnatural. Nobody would ever say 'In front of the door was seated a dog'. For a start, the inversion is awkward. Also, the use of 'to be seated' is very strange. If you say, for example, 'The audience must be seated by 7 pm', this means that the people must sitting on their seats by that time. People can be seated, but dogs are not normally seated.
I suspect this was written either by a non-native, or by a native speaker who had had their head in a grammar book for so long that they had lost sight of what a real English sentence sounds like. Don't waste your time on such awkward and pointless exercises.