Analyze the relationship between 'Worldpay' and 'London' within the context of the input sentence.
Options: founded by, headquarters location, parent organization, original broadcaster

British payments processor Worldpay joined the London Stock Exchange on Tuesday in an initial public offering valuing the company at 4.8 billion pounds ($7.4 billion), the biggest flotation in what had been a lacklustre year for listings in Britain.
headquarters location