You didn’t list any of the poems you’ve studied so I can’t be much help, sorry
I think it's the last one. I hope you find the right answer.
People should read lord of the flies because it has an interesting and surprising plot. Also because it shows the darker side of humans in cynicism that isn't very popular nowadays, which offers a refreshing point of view. Also it encourages deep self reflection about your own dark side and how you would honestly feel in a situation that the boys were in.