Utilize the input text as a context reference, choose the right relationship between aQuantive 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.

He previously held various management roles at aQuantive (acquired by Microsoft in 2007) and served as a consultant with Bain & Company.

Answer: parent_organization