What is the relationship between Boeing and Seattle in the context of the input sentence. Choose an answer from: 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.

Boeing's plan to set up a facility in China that would paint, finish and deliver 737 jetliners built at its factory near Seattle has provoked its largest union, representing about 35,000 Boeing employees.

Answer: location_of_formation