Final answer:
An author may use a third-person narrator to provide multiple perspectives, to delve into the thoughts and feelings of one character with a limited point of view, or to offer a more comprehensive and reliable narration with an omniscient point of view.
Step-by-step explanation:
An author might choose to use a third-person narrator for several reasons, including the ability to tell the story from multiple perspectives. In third-person limited narration, the narrator presents the story through the eyes of a single character, providing insight into that character's thoughts and feelings while limiting the perspective on other characters. This creates a more focused narrative, but it can present a somewhat biased view of the story.
Alternatively, third-person omniscient narration allows the author to share the thoughts and feelings of multiple characters, offering a broader understanding of the story. This mode is often used to provide a more reliable and objective narration, presenting all the facts and viewpoints in a story. It also allows for a more expansive and multifaceted telling of the narrative.
Lastly, third-person narrators are usually not characters in the story, which can make the narrative seem more impartial and less biased. This outside perspective can provide a broader angle of the story's events and a semblance of reliability not found in first-person narration.