Utilize the input text as a context reference, choose the right relationship between National Geographic Society and National Geographic 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.

The National Geographic Society and 21st Century Fox announced today that they have reached an agreement to expand their highly successful 18-year partnership through which they have owned and operated the properties in National Geographic Channels, a joint venture of domestic and international cable television channels which together reach more than 500 million households globally.

Answer: owner_of