Utilize the input text as a context reference, choose the right relationship between Airbnb and San Francisco from the options. Options: 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.

Some examples are Airbnb and Uber in San Francisco and TripAdvisor and Toast in Boston.

Answer: headquarters_location