Final answer:
The sentence that best identifies the purpose of the excerpt is to inform the reader of the narrator's experiences and reflections, particularly regarding an event where reliance on personal knowledge and training was crucial.
Step-by-step explanation:
The purpose of the excerpt is most closely related to expressing a theme or message through a personal anecdote. The answer that best identifies the purpose of the excerpt in question is likely: to inform the reader of the events that took place that resulted in the narrator being placed in Mrs. Gutzlaff's Mission School, as this aligns with Twain's intent to convey a message through his personal experience.
Considering the provided information about Mark Twain's excerpt, the author's main goal appears to be to reflect upon a personal experience and the importance of relying on one's own knowledge and training. It does not aim to entertain with a 'frightening account' or to argue that private education is superior to public education. Instead, Twain uses first-person narrative to enable readers to connect with his personal growth and realizations.
The purpose of the excerpt is to inform the reader of the events that took place and resulted in the narrator being placed in Mrs. Gutzlaff's Mission School. The author wants the audience to gain knowledge and understanding about the background and circumstances that led to the narrator's enrollment in this particular school.