The correct answer is d. all of the above.
The United States has an open class system that allows for various types of social mobility, including:
- Horizontal mobility: This refers to movement within the same social class or status (e.g., changing jobs within the same income bracket).
- Vertical mobility: This involves moving up or down the social hierarchy (e.g., achieving a higher income or social status).
- Intergenerational mobility: This pertains to changes in social status that occur from one generation to the next (e.g., children achieving a higher or lower status than their parents).
All these types of mobility contribute to the overall concept of social mobility within the U.S. class system.