We reached our new home about the time the State came in the Union. It was a wild region, with many bears and other wild animals still in the woods. There I grew up. There were some schools, so called; but no qualification was ever required of a teacher, beyond "readin, writin, and cipherin." Which type of humor does Lincoln use in this excerpt?

Lincoln sarcastically calls his former classmates wild animals.
Lincoln downplays his own intelligence to illustrate the quality of his education.
Lincoln uses sarcasm to describe the quality of the schools where he grew up.
Lincoln uses hyperbole to exaggerate the challenges of his education.