The word that best describes Mrs. Miller's tone is serious. The correct option is d.
The author's attitude or sentiment toward the topic they are discussing in a passage determines the piece's tone. The text's tone is unrelated to the reader's attitude toward the topic or the attitudes of any characters in the section except the author.
A story's tone conveys a specific emotion. It may be upbeat, somber, amusing, depressing, ominous, formal, casual, pessimistic, or optimistic. Your writing style will reflect how you are feeling at the time.
Therefore, the correct option is d. serious.
To learn more about the tone of the passage, refer to the link:
https://brainly.com/question/13871027
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