Final answer:
In social studies, the three main classes are the upper class, middle class, and lower class. Public class markers or traits can be shared, while personal financial information is generally private.
Step-by-step explanation:
In the context of social classes, there are typically three main classes: upper class, middle class, and lower class. The class members can be categorized into these three groups based on their income, wealth, and social status.
In terms of public and private members, it depends on the specific context, but generally, class markers or traits are public, while personal financial information would be private.