Answer:
D.
Explanation:
Basic Answer: In the late 1800s, workers organized unions to solve their problems. Their problems were low wages and unsafe working conditions. ... First, workers formed local unions and later formed national unions. These unions used strikes to try to force employers to increase wages or make working conditions safer.
I believe it is A, constantine the great built the city etc.
The answer would probably be use of iron and steel for weaponry also creating papyrus for written language