Who did the Roman leaders look back upon the ideas of this earlier civilization to improve society, culture, and politics to establish the Roman Republic?

The Roman leaders usually looked upon the ideas of Ancient Greece statesmen, philosophers and thinkers.

Explanation:

As many would argue Roman civilization is the continuity of Greek civilization. Although Rome conquered Greece they incorporated certain cultural, but also  political patterns into their own system. That is why we can see that even the leaders of Rome sometimes would back up the ideals of Greek society, especially of those who were seen as democratic.

i beleive that d is the right answer