Analyze the relationship between 'Singapore Airlines' and 'Singapore' within the context of the input sentence.
Options: headquarters location, parent organization, operator, brand

Airbus Launches New Ultra-Long Range Version of the A350-900 Enables Singapore Airlines to resume non-stop flights to the US Singapore Airlines (SIA) has selected Airbus' newly launched Ultra-Long Range version of the A350-900 for non-stop flights to the US.
headquarters location