Answer:
B. self-interest
Step-by-step explanation:
Adam Smith is considered the father of economic liberalism. Smith created a theory about the cause of the wealth of nations and a key element of his analysis was the individual behavior of economic agents. According to Smith, humans are selfish by nature and always seek the best for themselves - this is observed in Mark's greed for being rich. Thus a positive effect of each man's selfish and individual attitudes will be felt in the economy. When everyone seeks their benefits, the wheel of economics spins.