Final answer:
The population in New York, particularly New York City, saw a significant increase in 1849 due to industrialization and the rise of urban centers, which provided new employment opportunities. Option A is the correct answer.
Step-by-step explanation:
By observing the patterns of settlement and population growth in the United States during the 19th century, it becomes clear that the area which saw a significant increase in population in 1849 was New York. The rapid industrialization that began in the mid-1800s led to the growth of urban centers where employment opportunities were abundant. In particular, New York City's population exploded due to these new opportunities, with the population skyrocketing from 33,000 in 1790 to 270,000 by 1825, indicating an already significant growth prior to 1849. And as cities like Chicago and Philadelphia also grew, New York held a notable lead in terms of urbanization and population increase, primarily due to its commercial centers and the influx of immigrants seeking economic opportunities.