What did Constantine do to help reunite the empire? He forced all Roman citizens to pledge allegiance to him.
He moved the capital to a better location for defence and trade.
He cut the size of the empire to make it more manageable.
He made Christianity the sole religion, to unite everyone.

Found this off of google, "Constantine now became the Western Roman emperor. He soon used his power to address the status of Christians, issuing the Edict of Milan in 313. This proclamation legalized Christianity and allowed for freedom of worship throughout the empire. ... In 324, Constantine defeated Licinius and took control of a reunited empire."

So, the answer to your question is D)He made Christianity the sole religion, to unite everyone.

Hope this helps have a great day and stay safe! :) :D :3

he moved the capital for defense and trade

Explanation:

the great wall of china worked as a defense for the feudal states of the zhou dynasty to the north. during the warring states period more walls were put up to defend the borders of the different kingdoms. it was semi successful because despite the wall, the mongols eventually conquered china also the great wall provided protection to the economic development and cultural progress, safeguarded the trading routes such as the silk road, and secured transmission of information and transportation. @jayxboof

b. the passage of the equal rights amendment  

explanation:

this mean that anything that someone else could do they could do