Paul Romer Speaks About the Significance of "Charter Cities

Paul Romer speaks about the significance of "charter cities." What are these?

A) They are cities that have a contract with their host government to provide raw materials and labor for export and economic expansion.
B) They are cities that are focused on specific types of "theme" production,such as textile production,mineral excavation,or micro-chip technologies.
C) They are cities within nation-states that are administered by outside (and wealthier) nations under a separate set of rules than those of the host countries.
D) They are cities that are administered by a United Nations agency that works to create profitable jobs and social security for all needy members of the society.
E) They are cities that have a separate constitution that allows them to operate under laws that usually conflict with the host country.