Answer:
d. Tarquins / republic
Step-by-step explanation:
Option A is not correct as Romans citizens didn't fought against Greeks to established this form of government. The war against Macedonian Kingdom that held Greece happened in 2nd Century BC.
Option B is not correct as Byzantine Empire is the continuation of Roman Empire.
Option c is not correct as although Romans fought the Etruscans it wasn't to establish oligarchy, but to establish a more flexible system.
Option D is correct as Romans overthrew the last Roman king Tarquin the Proud and established Republic in 509 BC.