..I turn
this way-the stone lets me go

well stockyards mean a large yard containing pens and sheds, typically adjacent to a slaughterhouse, in which livestock is kept and sorted. and i'm assuming that by party you   mean a large group of people which does make sense because chicago is a very crowded place much like new york. stockyards tend to take up a lot of room due to needing the area for pens to keep animals in and the fact that stockyards are usually right by slaughterhouse where they process and distribute the product. so its much like a zoo but with some dead animal products close by.

op: object of preposition

? ? what can you explain this to me i am so confused

this answer to this question is c. allegory

why?

stories with allegories have a hidden symbolic meaning with a theme. the hidden meaning can be political, or other real life problems.