Read the information below:
In 1840, the population of Chicago was only 4,470. By 1900, the city's population was 1,698,575.

Which factor best explains the population change?
The construction of railroads connecting Northeastern cities and Midwestern farms
The reduction in immigration quotas on Southern and Eastern Europe
The spread of government housing for low-income workers throughout U.S. cities
The successes of the Settlement House Movement

Question

Read the information below: 
 In 1840, the population of Chicago was only 4,470. By 1900, the city's population was 1,698,575.
 
Which factor best explains the population change? 
The construction of railroads connecting Northeastern cities and Midwestern farms 
The reduction in immigration quotas on Southern and Eastern Europe 
The spread of government housing for low-income workers throughout U.S. cities 
The successes of the Settlement House Movement