Refer to the input text as context and select the correct relationship between 'Heathrow hub' and 'London' from the available options.
Options: publisher, headquarters location, founded by, distributed by

A clue to BA's lingering love affair with the 747 lies in the model's ability to eke out capacity from scarce operating slots at its London Heathrow hub at a time when lower fuel prices make retaining older planes an option.
headquarters location