I think it's D. The use of farming to feed a larger population.
The sentence that correctly describes the living conditions of workers during industrial period is :
A. Row houses and tenements were terribly overcrowded
D. Poor sanitation and polluted water spread diseases like typhus, cholera, and smallpox
Back then, worker earn very little and they still cannot afford a proper living
hope this helps
I think it might be Freedom of Speech, not really sure though.