What is the relationship between Glencore and Marc Rich in the context of the input sentence. Choose an answer from: 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