A class system is a form of social stratification that is relatively open, allowing for social mobility. It is based on both social factors, such as family background and inherited status, and individual achievement, such as education, occupation, and income. Because both ascribed social factors and achieved individual merit play significant roles in determining one's position within the class hierarchy, both options A and B are correct.

The objective method of social class identification relies on quantifiable data. By using standardized metrics like annual income, occupational prestige scores, and years of formal education, researchers can categorize individuals into distinct socioeconomic classes without relying on subjective perceptions or social reputation.

In the feudal system, the lower class, specifically serfs and peasants, provided the labor required to cultivate the land within a lord's fiefdom. While the elite class owned the land, the actual agricultural production and physical maintenance were performed by the lower classes.

In sociology, a social class is defined as a group of individuals who share a similar position in the social hierarchy based on economic criteria, including income, wealth, and occupational prestige. These factors influence an individual's life chances, social opportunities, and access to resources, effectively categorizing them within the broader structure of social stratification.

Sociological studies on social stratification often highlight that upper-middle-class families prioritize professional degrees that offer high social status, job security, and significant earning potential. Fields such as business, law, and medicine are traditionally viewed as prestigious pathways that facilitate the maintenance of class position and intergenerational social mobility within this demographic.

The 'young-old' demographic, typically referring to individuals in the early stages of retirement (often ages 65-74), is frequently characterized by better health, higher levels of happiness, and greater financial stability compared to the 'old-old' demographic. These individuals often remain active, engaged in social roles, and possess the resources necessary to maintain a higher quality of life during their transition into later adulthood.

Social class is a complex construct determined by a combination of factors. Birth (ascribed status) can influence initial opportunities, while money (economic capital), education, and occupation (achieved status) are critical indicators of one's position in the social hierarchy. Together, these elements define an individual's access to resources and their overall social standing.

Infant mortality is strongly correlated with socioeconomic status. Professional groups generally have higher incomes, better access to quality healthcare, and more resources to support maternal and infant health. These factors contribute to lower infant mortality rates compared to manual or lower-skilled occupational groups, highlighting the impact of social stratification on health outcomes.

The embourgeoisement thesis emerged in the mid-20th century, suggesting that as working-class families became more affluent, they would increasingly adopt the lifestyle, consumption patterns, and political values of the middle class. This theory argued that the traditional working-class identity was eroding as economic prosperity allowed for greater social integration into the middle-class mainstream.

Income is defined as the flow of money received by an individual or household over a specific period, typically through employment wages, salaries, or investment returns like dividends. It is a primary indicator of economic status and is distinct from wealth, which refers to the total value of accumulated assets.