What is the relationship between EU and European Union 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.

The European Union has moved to change its diesel car emission tests to prevent the sort of rigging used by German car giant Volkswagen after noticing discrepancies in the results, EU sources say.

Answer: operator