If you had to read one of these books...?

If your only criteria is that it be short enough, then you can determine that for yourself. On the other hand, if you want to read a book that will teach you something about life, and leave you with a lasting impression, I recommend The Chosen, or Cry, The Beloved Country (one of my favorite books, ever, and I've read a LOT of books) or A Tree Grows in Brooklyn.