England treated the colonists unjustly, which is why they revolted against the crown and created their own nation. So the answer would be D. I hope this helps :)
Railroad industry which now had laws Government conduct
Answer:
The poorer areas of the cities were characterised by overcrowded, badly built, unsanitary living accommodation, and filthy streets. Cholera, carried by dirty water, killed 16,000 Londoners in 1849 alone, and smallpox, scarlet fever, typhus, scurvy and rickets were rife.