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.
What is the relationship between 'National Geographic Society' and 'National Geographic' in the context of the input sentence.
Options: subsidiary, employer, headquarters location, owner of