This is a quote by Ayn Rand, in the rest of this anthem she goes on to explain how being part of that we can sometimes be harmful. So the answer is The comparison of the word “We” to limestone helps to develop the theme that a collective society destroys humankind’s potential. You can see this in that bit of the quote when she says it "crushes all beneath it"
The answer you're looking for is B
Olaudah Equiano wrote a book, which was about his experiences as a slave and, later, as a free man. Hope this helps <3