Utilize the input text as a context reference, choose the right relationship between Resolution Copper and copper from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

Opponents also point to the foreign owners of Resolution Copper Mining, a subsidiary of British-Australian Rio Tinto and Australian BHP Billiton, saying it's unclear how much of the profits and the copper will stay in the U.S.

Answer: product_or_material_produced