Which important change did the rise in popularity of the radio broadcasting in the 1920s cause in US society? A) The Hollywood studio system lost its hold on entertainment as a new wave of radio stars became popular. B) Regional dialects largely disappeared as Americans began to emulate the voices they heard on the radio. C) The popularity of newspapers and magazines plummeted as Americans began to get all of their news from the radio. D) A new mass culture emerged, along with mass marketing techniques to influence the public.