Answer:
all of the above were Douglas' audience but the most influenced people amongst the above were abolitionists.
Huck seems like the type of character, based just from this snippet, to overexaggerate things, even something small. He also seems to be on the glass half empty side of life. Perhaps cocky and a bit overzealous, too, judging by the "I bet I do" phrase. Does that help?
The answer to your question is:
Classmates; to inspire and persuade them to earn good grades
