Answer: A. Stratification
Social stratification describes the categorization of people in a society into groups based on factors like income, race, ethnicity, wealth, gender, occupation, etc. While society is not limited only to complex societies, every complex society in the world today shows features of stratification. Globally, the stratification is quite evident and this sometimes leads to the unequal distribution of wealth, capital, and other resources among groups of a region and even between nations.