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.

Thank you :)

Yes, B is what I would choose as the correct answer. For A to be correct, it would have to be "In front of the door sat a dog". Correct, C and D require the verb "to sit" (C-sat a dog / D-was a sitting dog)

In front of the door was seated a dog => B (be seated = sit down so we can't choose C or D right?)

I shall give you a hint. Inversion means "verb-subject order" instead of the normal "subject-verb order". In normal subject-verb order, we would say: NORMAL ORDER INVERTED ORDER "A dog was seated in front of the door." => In front of the door _____ (verb-subject) "A dog sat in front of the door." => In front of the door _____ (verb-subject) Based on this hint, which answer do you think is correct?