The movement of people or population from rural areas to the urban area is referred to as Urbanization
Explanation:
In US urbanization started in early 1800s. In the year 1890 ,8% of the Americans shifted in urban areas with marked the era of urbanization
Industrialization in US can be categorized in two phases:
First Phase :This phase saw the rise of factories and mechanized Production.It started in late 1700s
Second Phase:This phase witnessed the invention of telegraph,locomotives,steamboats,steam-powered spinning and weaving machines.
The answer to the above question is (A) Gradual Urbanization and industrialization.