What factor of roman civil society long outlasted the empire

This question is incomplete, here´s the complete question.

What factor of Roman civil society long outlasted the empire?

The unquestioned authority of the paterfamilias  

The system of patronage

The idea of citizenship for all adult males  

The legal system and extensive written laws

The legal system and extensive written laws.

Explanation:

Ancient Rome developed a legal system and thorough written laws that influenced people long after the decay of the Roman Empire and even in places never before under Roman rule.

The roman law remained during the Byzantine Empire until 1453, and the legal system has influenced most Western and East civilizations and is the foundation of European law codes and derivative systems elsewhere.

the answer is d. give brainliest if right.

ps is this 7th grade civics?

yes i can of course like what is it gonna be about