Which of the Following Is the Argument Used by Proponents

Which of the following is the argument used by proponents of the "cultural" explanation for the difference in economic development across the globe? 

A)  That rich countries have a smarter and harder-working population 
B)  That rich countries tend to be endowed with natural resources 
C)  That rich countries tend to have better market-supporting institutions 
D)  That rich countries generally tend to have a democratic style of government