10. Why does Mark Twain use dialect when Wheeler tells the story?
A The use of dialect makes the characters more realistic, adding a
serious element to an otherwise humorous story.
B The use of dialect underscores the exaggerated qualities of the
characters and separates the narrator from the story.
C The use of dialect makes it harder to understand, so readers have to
pay more attention to the progress of the story.
D The use of dialect makes the characters seem more intelligent, so
readers take them and the story's message more seriously.

Twain is one of most known realists of all time. He is acknowledged for the portrayal of real-life subjects in authentic and true-to-life manner. The speech pattern that he offers to his characters allows the audience to connect with them naturally as they depict real-life situations in usual language.

As per the question, Twain uses the dialects when Wheeler relates the story as it assists in emphasizing the amplifying qualities of the characters that offers a realistic view for the audience to connect themselves to the narrative and separates the narrator which could affect the naturalistic impression. Thus, option B is the correct answer.