What is the relationship between British Gas and Centrica 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.

Peter Atherton, analyst at Jefferies investment bank, said that the cost to take control of just the UK assets of companies, which include British Gas owner Centrica and network operator National Grid, would drain about £124bn from the nation's coffers.

Answer: owned_by