题目内容：
Modern computers based on （ ）are millions to billions of times more capable than the early computers， which occupy a fraction of the space. Simple computers are small enough to fit into mobile devices， and mobile computers can be powered by small batteries. Personal computers in their various forms are icons of the information Age and are what most people think of as ‘computers’.
A.central processing unit
B.integrated circuits
C.hard disk
D.software integration
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答案解析：