Final answer:
The narrative voice in 'The Story of an Hour' is that of an omniscient narrator who describes the actions and motivations of various characters without directly revealing Mrs. Mallard's inner thoughts or feelings.
Step-by-step explanation:
The narrative voice in the excerpt from "The Story of an Hour" best fits the description of an omniscient narrator. This type of narrator has full knowledge of the story's events and characters' thoughts and feelings. In the provided excerpt, the narrative voice reveals the actions and motivations of Josephine and Richards, as well as the context of the railroad disaster, without the personal involvement one would expect from a character within the story. It does not, however, reveal Mrs. Mallard's inner thoughts or feelings directly, indicating that an omniscient narrator is used to tell the story rather than a character narrator.