In the late 1800s, cities expanded rapidly due to industrial growth, and tens of thousands of workers moved into urban areas. Tenement housing emerged as dense, cheap multi‑unit buildings designed to pack as many people as possible into a small footprint near factories. They were typically several stories high, with small rooms, limited light and ventilation, shared bathrooms, and poor sanitation. Fire hazards and crowding were common, reflecting the pressure to provide inexpensive shelter for a booming workforce. That’s why this option best describes tenement housing. Detached cottages on the outskirts represent suburban or rural styles, not inner-city worker housing. High‑rise luxury apartments for executives and large single‑family homes with yards were not the norm for late‑19th‑century tenements, which were built for affordability and high density among laborers.

The idea behind focusing on sanitation, clean water, and sewers is that preventing disease was the gateway to healthier, more productive cities. As urban populations exploded in the late 1800s, outbreaks of deadly illnesses like cholera and typhoid spread rapidly through contaminated water and filth. With the growing acceptance of germ theory, reformers saw that disease could be dramatically reduced by removing waste, ensuring safe drinking water, and properly draining sewage. These improvements cut mortality and illness, which meant a stronger, more reliable workforce and a more stable urban economy. The drive was about public health and practical benefits for city life, not private profit, immigration policy, or reducing taxes.

Nativism is the belief that a country should be for native-born people, prioritizing the interests of those born in the country over immigrants, and often calling for restricting immigration. This is the idea behind the phrase “America for Americans.” It best matches the concept because it centers native-born citizens and limits on newcomers, whereas the other options describe welcoming immigrants, giving them welfare, or embracing multicultural education, which are opposite in focus. In discussions of immigration and urbanization, nativist attitudes influence debates over who belongs in the public sphere and who gets access to resources.

National-origin quotas were used in the 1920s to limit immigration by country of origin. The Immigration Act of 1924, also known as the National Origins Act, established annual numerical limits for each country and tied those limits to a percentage of that nationality living in the United States (based on the late-19th-century census). This approach intentionally favored immigrants from Northern and Western Europe while sharply reducing entries from Southern and Eastern Europe and virtually excluding most Asian immigration. That direct creation of a national-origin quota system in the 1920s is why this option is the best answer. The other laws listed either targeted a single group from earlier decades or addressed different issues entirely (land distribution or civil rights).