The Civil War resulted in an economic boom for the United States, which saw an unprecedented industrial development in which part of the country?

The founder of the byzantine  empire  and its first  emperor,  constantine  the great,  movedthe  capital of the roman empire  to the city of byzantium in 330 ce, and renamed it  constantinople.  constantine  the great also legalized christianity, which had previously been persecuted in the  roman empire.

Im going to say its either a or d but im leaning more to d