Since the 1970s, income in the U.S. has increasingly polarized: it has disproportionately increased for the top 1% of earners but remained relatively static for the lower 80%, while the size of the "middle-class" has decreased. As a result, the top 1% of income earners increasingly controls major political and cultural institutions, fewer businesses cater to the "middle-class," and many feel they have little chance of upward economic mobility. Which of the following best represents a sociological analysis of this scenario?

A. Structural forces affect social life at the individual level of society.
B. Structural forces affect social life at the group level of society.
C. Structural forces affect social life at the institutional level of society.
D. All of the above.