The pax romana ended in 180 ce after over one hundred fifty years in existence. the end of this era ushered in a period of
a. inflation.
b. foreign wars.
c. religious wars.
d. political instability.

D. political instability.

Explanation:

The Pax Romana is a period when there were peace and stability across the Roman Empire that lasted for over one hundred and fifty years. The end of this era ushered in a period of great instability, where there were civil wars leading to the division of the empire, political conspiracies leading to in many senators been assassinated and provincial and slave rebellions.  

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.

hello answer is b i hope that helepd.