Mass production, the defining characterist

问题：

Mass production, the defining characteristic of the Second Wave economy, becomes increasingly obsolete as firms install information intensive, often robotized manufacturing systems capable of endless cheap variation, even customization. The revolutionary result is, in effect, the demassification of mass production.

The shift toward smart flex techs promotes diversity and feeds consumer choice to the point that a Wal-Mart store can offer the buyer nearly 110,000 products in various types, sizes, models and colors to choose among. But Wal-Mart is a mass merchandiser. Increasingly, the mass market itself is breaking up into differentiated niches as customer needs diverge and better information makes it possible for businesses to identify and serve micro markets.

Specialty stores, boutiques, superstores, TV home-shopping systems, computer based buying, direct mail and other systems provide a growing diversity of channels through which producers can distribute their wares to customers in an increasingly demassified marketplace. When we wrote Future Shock in the late 1960s, visionary marketers began talking about "market segmentation". Today they no longer focus on " segments" but on " particles "—family units and even single individuals. Meanwhile, advertising is targeted at smaller and smaller market segments reached through increasingly demassified media.

The dramatic breakup of mass audiences is underscored by the crisis of the once great TV networks, ABC, CBS, and NBC, at a time when Tele-Communications, Inc. of Denver, announces a fiber optic network capable of providing viewers with five hundred interactive channels of television. Such systems mean that sellers will be able to target buyers with even greater precision. The simultaneous demassification of production, distribution and communication revolutionizes the economy and shifts it from homogeneity toward extreme heterogeneity.

Why are great TV networks, ABS, CBS and NBC mentioned in the passage（）

A. As examples of breakup of mass audiences

B. In comparison with Tele-communications, Inc. of Denver

C. To show their capability of providing lots of channels

D. To present their prosperity in advertising among viewers