What is the relationship between grocery and Walmart 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.

A&P bankruptcy: Part 2 Not too long ago the biggest retailer in the country was not Walmart ( WMT ), but The Great Atlantic and Pacific Tea Company -- better known as the grocery store chain A&P.

Answer: operator