What affect did the factories have on the population of cities in the 1800s

B.

The population increased with the amount of immigrants coming into the U.S, due to the building of factories, going along with the Industrial Revolution-

i think its A, if the factories caused pollution, then people would want to move away from the pollution, causing the population to decrease. if the factories benefited the city and made it stand out to others, then it would be B. If the factories didnt make a difference to the city, it would be C.

personally, i think its A, but if there is a story/passage with it, then read it and see for anything i said. sorry if i didnt help.

I'd go with A. hope it helps!:)