Utilize the input text as a context reference, choose the right relationship between Viacom and CBS 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.

Viacom (NasdaqGS: VIAB - news ) fell 7.5 percent, 21st Century Fox lost 7.0 percent, CBS shed 4.6 percent and Comcast dropped 4.7 percent.

Answer: parent_organization