What is the relationship between Balfour Beatty and LONDON 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.

LONDON (Reuters) - British infrastructure group Balfour Beatty (BALF.L) issued a fresh profit warning on Thursday, saying it had found further problems in its business which are likely to tip it into another loss for 2015.

Answer: headquarters_location