I’d say C, since it says “ever-changing” meaning that is will never be anything but different.
Disparate implies that something is very different and not allowing comparison. A nation built on ever-changing differences without any similarities.
The nation was built on the notion that men were created equal, which was how it was supposed to be; however, “most men consider themselves better than someone.” This would be the disparate part. Kinda like something is completely different than what it was intended to be like.