The nations of opec chose to cooperate primarily in order to lead regional development efforts encourage the growth of trade among one another provide a forum for international justice manage the supply of a natural resource assure mutual self-defense from attack

D. manage the supply of a natural resource

Explanation:

OPEC is the abbreviation of Organization of the Petroleum Exporting Countries which is established at 1960. Its primary objective is coordinate the petroleum prices and ensure the market stabilization for petroleum products. In today’s world they are highly influential powers in the petroleum products. OPEC member countries are present in Asia, Africa, North America and South America such as Algeria, Angola, Congo, Ecuador, Equatorial Guinea, Gabon, Iran, Iraq, Kuwait, Libya, Nigeria, Saudi Arabia, United Arab Emirates and Venezuela.

answer; surplus food; is the correct answer; ///