Because over time things change. An example of that would be back in the 1800's they rode horses as transportation today we ride cars and aeroplane as transportation.
From what I remember, children in Sparta were pushed towards military. If a child was found to be weak, then they were left for dead. In Athens, they were pushed towards academics and arts. I think that's the main difference.
Im gonna say D because its the only option that dosnt sound insane hahahah
B. Discrimination in employment based on race was banned.