单项选择题
The following paragraph is incomplete. Choose the best sentence to make it complete. 选择合适的句子，完成段落。
There are a lot of terms used to describe computers. Most of these words imply the size, expected use or capability of the computer. ___________________________________. The most familiar type of microprocessor is the personal computer (PC). It is designed for general use by a single person. Another purpose for using a microprocessor is as a workstation. The computers used for this purpose have a more powerful processor, additional memory and enhanced capabilities for performing a special group of task, such as 3D Graphics or game development. A computer can also be used as a server. Servers usually have powerful processors, lots of memory and large hard drives. A fourth one, a main frame is the heart of a network of computers or terminals which allows hundreds of people to work at the same time on the same data.
A．The process a computer works involves several steps that call for our attention.
B．The impact of computer on modern society is beyond what we expect.
C．Computers can be divided into several types according to the purpose they are used for and their capabilities.
