Which one takes the least amount of time?

I have to read one of four books by the end of October for school and as I'm really busy at the moment I was hoping someone could help me by telling me which book takes the least time to read? I dont have any physical copies of the books to hand, so I can't compare myself. I have to pick one of the following:
Tom Jones - Henry Fielding
Middlemarch - George Eliot
Great Expectations - Charles Dickens
North and South - Elizabeth Gaskell
Also, if any of you have read any of them, did you enjoy them?