I already answered the question but here it is again:
The correct answer is B. to keep readers from realizing at the start that no humans are present.
Indeed, Bradbury’s story is intended to warn readers that the inevitable consequence of an all-out nuclear war is the extinction of the human race. His story is inspired by the much earlier poem from American poetess Sarah Teasdale, who wrote the poem of the same title in the aftermath of World War I, which until then had been the most devastating conflict in the history of the world at that time. Since the house is a mechanical entity; it stresses the fact that it was built by humans but since no humans are present anymore, their absence is all the more noticed and the, dramatic impact for readers is stronger and everlasting.
Third Person omniscient means that the narrator can not only hear the protagonists thoughts but also everyone else. Therefore the story can be told from may different perspectives. Hope it helped :)
When trying to convey the thoughts and feelings of immigrant laborers in the early 20th century, it would be best to read a narrative type of passage, due to the story.
