Analyze the relationship between 'Betfair' and 'online gambling' within the context of the input sentence.
Options: platform, industry, product/material produced, distributed by

Betfair Group Plc (LSE: BET.L - news ) and Irish rival Paddy Power Plc (LSE: PAP.L - news ) , both licensees of Playtech, on Wednesday agreed to a 5 billion pound merger, to stake a claim to leadership of Britain's online gambling market.
industry