资料：The personal computer was a revolution in information technology that spawned a $50 billion hardware business, with another $30 billion in software and peripherals （eg. mouse, keyboard, printer, etc.） by 1991. During its short 15 years, the industry evolved through three successive periods. During its first 5 to 6 years, it was characterized by explosive growth and multiple, small competitors vying for a piece of the market. From 1981 to 1985, the industry became a battle for standards and retail shelf space. The third era was one of increasing fragmentation. From 1986 through 1991-1992, new manufacturers from around the world grabbed from the industry leaders as new channels of distribution emerged and product innovation as well as revenue growth slowed.
During the early years of the industry, venture capital in the U.S. encouraged the entry of new firms that offered products in every conceivable shape and size. By 1980, new entrants flooded the market, prompting distinct standards and unique technical features. Almost every firm had a different configuration of hardware and software. The first PC had relatively little speed or memory. However, even these early computers allowed managers to perform tasks that were very time consuming.
What happened in the third era?
A.The small companies experienced a harsh life.
B.People preferred PCs of big brands.
C.The big companies didn’t earn as much as they did in the past two periods.
D.The companies made standards on the configuration.
