What is the relationship between Walkman and Sony 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.

Around the same time that teams at Sony starting exploring ideas about a digital Walkman in 1999, Steve Jobs, the CEO of Apple, sat down with a team of engineers to try to create his own digital music experiment.

Answer: manufacturer