Utilize the input text as a context reference, choose the right relationship between Windows Phone and Microsoft 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.

Microsoft has failed to get much traction for its Windows Phone platform even with the acquisition of Nokia.

Answer: developer