Analyze the relationship between 'Centrica' and 'British Gas' within the context of the input sentence.
Options: headquarters location, brand, distribution format, owner of

The competition watchdog said in March that it had granted permission for British Gas Trading (BGT) - a subsidiary of Centrica (LSE: CNA.L - news ) , the UK's biggest energy supplier - and Northern Powergrid to appeal against Ofgem's price control decision.
owner of