Given the input sentence, please extract the subject and object containing a certain relation in the sentence according to the following relation types, in the format of "relation1: word1, word2; relation2: word3, word4". Relations include: 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 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.

Answer: owner_of: Centrica, British Gas; owned_by: British Gas, Centrica