Final answer:
Social class in the United States is defined by multiple factors such as wealth, income, education, family background, and occupation, and is not solely based on income or any other single factor.
Step-by-step explanation:
According to the textbook, one conclusion we can draw about how social class is defined in the United States is c) It's influenced by multiple factors. Social class in the U.S. is a grouping based on similar levels of wealth, income, education, family background, and occupation.
While income does play a significant role, and is primarily based on one's value to an employer—which depends in part on education—it is not the sole determinant of social class. Additionally, the class system in the U.S. is open, meaning individuals have the ability to change their social class through education and employment opportunities, indicating that social class is not static and unchanging.