Which of the following defines centralization with the answer be the movement of population to cities, the increase in national power, the simplification of the laws or is it the preference for immigrants from Europe

The definition of centralization among the given options is "the increase in national power." Centralization refers to the concentration of power and authority in the central government or a central authority figure within a country. The movement of population to cities, the simplification of laws, and the preference for immigrants from Europe are not accurate definitions of centralization in this context.