Utilize the input text as a context reference, choose the right relationship between Starbucks and coffee 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.

In a conference call with investors July 23, Starbucks executives disclosed that they had already locked in the price for more than 80 per cent of coffee supplies for 2016.

Answer: product_or_material_produced