Utilize the input text as a context reference, choose the right relationship between Glencore and Marc Rich 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 March, Glasenberg predicted confidently that oil trading - the historic core of the company which began as Marc Rich in the 1970s and was renamed Glencore in the 1990s - could "blow out the lights in 2015".

Answer: founded_by