Q:Information:  - British Airways, often shortened to BA, is the flag carrier and the largest airline in the United Kingdom based on fleet size. When measured by passengers carried, it is second-largest in the United Kingdom behind easyJet. The airline is based in Waterside near its main hub at London Heathrow Airport.  - London Stansted Airport is an international airport located at Stansted Mountfitchet in the local government district of Uttlesford in Essex, northeast of Central London and from the Hertfordshire border.  - An international airport is an airport that offers customs and immigration facilities for passengers travelling between countries. International airports are typically larger than domestic airports and often feature longer runways and facilities to accommodate the heavier aircraft commonly used for international and intercontinental travel. International airports often also host domestic flights. Some, such as Frankfurt Airport in Germany are very large; others such as Fa'a' International Airport in Tahiti, are quite small.  - EasyJet (styled as easyJet) is a British airline, operating under the low-cost carrier model, based at London Luton Airport. It operates domestic and international scheduled services on over 820 routes in more than 30 countries. easyJet plc is listed on the London Stock Exchange and is a constituent of the FTSE 100 Index. easyGroup Holdings Ltd (the investment vehicle of the airline's founder Sir Stelios Haji-Ioannou and his family) is the largest shareholder with a 34.62% stake (as of July 2014). It employs nearly 11,000 people, based throughout Europe but mainly in the UK.  - Go Fly ( styled and trading as Go ) was the name of a British low - cost airline , founded by British Airways ( BA ) in 1998 . It operated flights between London Stansted Airport and destinations in Europe . The airline was purchased from BA in a management buy - out backed by the private equity firm 3i in 2001 . In 2002 it was bought by its rival EasyJet , and was merged into the airline 's operations . Its head office was in the Enterprise House in London Stansted Airport in Stansted Mountfitchet , Essex .  - London is the capital and most populous city of England and the United Kingdom, as well as the most populous city proper in the European Union. Standing on the River Thames in the south east of the island of Great Britain, London has been a major settlement for two millennia. It was founded by the Romans, who named it "Londinium". London's ancient core, the City of London, largely retains its medieval boundaries. Since at least the 19th century, "London" has also referred to the metropolis around this core, historically split between Middlesex, Essex, Surrey, Kent, and Hertfordshire, which today largely makes up Greater London, governed by the Mayor of London and the London Assembly.  - 3i Group plc is a multinational private equity and venture capital company based in London, United Kingdom. 3i is listed on the London Stock Exchange and is a constituent of the FTSE 100 Index.    What object entity has the relation of 'airline hub' with the subject 'go '?   Choices: - frankfurt airport  - heathrow airport  - london stansted airport  - luton airport  - split
A:
luton airport