What is the relationship between Betfair and online gambling 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.

Betfair and Irish rival Paddy Power have agreed in principle on a 5 billion pound ($7.85 billion) merger to stake a claim to leadership of the online gambling market in Britain.
industry