Take context from the input text and decide on the accurate relationship between 'Lyft' and 'San Francisco' from the options provided.
Options: chairperson, legal form, brand, headquarters location

San Francisco startup Lyft Inc. and Chinese startup Didi Kuaidi Joint Co. said Wednesday they have formed an alliance to allow users of each app to hail rides from drivers of the other app while they are traveling to the other country.
headquarters location