In the united states today, very few people marry outside of their own socioeconomic class, suggesting that there is a high degree of:

I believe the answer is: Endogamy

Endogamy refers to a custom that require the people to be married only to someone from their close social group.
For most endogamous society, the parents of the couples would most likely played a huge influence in the coupling, which resulted in less free will between the couple

Fiscal policy because it refers to the use of government spending and tax policies to influence macroeconomic conditions, including aggregate demand, employment, inflation, and economic growth.