Answer:
Correct answer is D. Their form of government has influenced the democratic governments of today.
Explanation:
Option A is not correct as government was far from weak, and government managed to strengthen the authority of the country and to create one of the strongest countries in history.
Option B is not correct as democratic principles existed even before, for example in Athens.
Option C is not correct as it is very relevant, and a large number of countries today have adapted their systems according to the systems of Roman republic.
Option D is correct as many countries, as we have said, for example United States have created their governments according to what existed in Roman Republic.