A、Printing. B、Television. C、Record pressing. D、Film duplication. B文章在谈到大众传媒简要历史时提到了一些例子，据此可以排除不相干选项，答案是B

Mass media is the term used to denote, as a class, that section of the media specifically conceived and designed to reach a very large audience. It emerged in the 1920s with the advent of nationwide radio networks and of mass-circulation newspapers and magazines.
    Media is a contraction of the term media of communication, referring to those organized means of dissemination of fact, opinion, and entertainment such as newspapers, magazines, cinema films, radio, television, and the World Wide Web.
    During the 20th century, the advent of mass media was driven by technology that allowed the massive duplication of material at a low cost. Physical duplication technologies such as printing, record pressing and film duplication allowed the duplication of books, newspapers and movies at low prices to huge audiences. Television and radio allowed the electronic duplication of content for the first time.
    In a democratic society, an independent media serves to educate the public about issues regarding government and corporate entities.
    During the last decade of the 20th century, the advent of the World Wide Web marked the first era in which any individual could have a means of exposure on the scale of mass media.