What is the relationship between Bharti Airtel and Vodafone 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.

The de-linking of licences from spectrum wherein spectrum had to be bought in open auctions ensured that only serious operators remained in the game and led to a scenario where only three operators — Bharti Airtel , Vodafone India and Idea Cellular—consolidated their market position cornering around 75% of the subscriber market.

Answer: owned_by