Two Secondary Causes of the Extraordinary Variation in Output Per

Two secondary causes of the extraordinary variation in output per worker between countries today are

A) openness to creating and adapting technologies that enhance the efficiency of labor and the level of education today.
B) openness to free trade and the level of education today.
C) openness to democratic institutions and to creating and adapting technologies that enhance the
Efficiency of labor.
D ) openness to creating and adapting technologies that enhance the efficiency of labor and reducing the role of government in the economy.