Throughout the pax romana, one of the strongest unifying forces in the empire in the empire was the government. Option D is correct.
The Pax Romana was a protracted period of relative peace and stability that the early Roman Empire experienced. It is believed to have started with the accession of Caesar Augustus, founder of the Roman principate, in 27 BCE and ending in 180 CE with the death of Marcus Aurelius, the last of the "good emperors".