What is OPEC, and why does it matter?

OPEC is the Organization of the Petroleum Exporting Countries. It's an intergovernmental body with a mission to, 'coordinate and unify the petroleum policies of its member countries and ensure the stabilization of oil markets, in order to secure an efficient, economic and regular supply of petroleum to consumers, a steady income to producers, and a fair return on capital for those investing in the petroleum industry.'

Show the interviewer that you have an understanding of OPEC and how it affects the way Marathon Petroleum does business.