The correct answer is C: to make the reader comfortable with the character.
Explanation:
Mark Twain uses a conversational tone when writing from Huckleberry Finn's perspective to make the reader comfortable with the character. He tries to make Finn's character more approachable and closer to the readers, in order to expand the scope of the reader's view. Huckleberry's tone is friendly, naive, and a little bit uneducated, but despite that, he manages to gain sympathies of the readers.
