D$.(1)$ The history of the computer, though it covers less than seventy years, can be divided into five distinct generations. $(2)$ Computers from the first generation, from $1940$ to $1956,$ used vacuum tubes for circuitry and were huge, taking up whole rooms. $(3)$ Punched cards were used to input information. $(4)$ Output came from printouts on reams of paper. $(5)$ One such massive machine, UNIVAC, became the first computer to have a commercial client, the U$.$S$.$ Census Bureau. $(6)$ When transistors came along to replace tubes, the second generation of computers was born. $(7)$ The first computer languages, such as FORTRAN and COBOL, were invented for these machines. $(8)$ In $1964$ integrated circuits came into use, with much smaller transistors attached to silicon chips. $(9)$ These third$-$generation computers were smaller and more powerful and found many uses in businesses, research, and education. $(10)$ They also ushered in the use of the keyboard and monitor. $(11)$ The fourth generation began in $1971$ with the introduction of microprocessors and continues to this day. $(12)$ The leap forward was that thousands of circuits were attached to one silicon chip. $(13)$ Now all the main functions of the computer could be put on one chip, called the central processing unit, or CPU. $(14)$ In $1981$ IBM became the first company to sell a computer for home use, and in $1984$ Apple introduced the Macintosh. $(15)$ Today we are on the threshold of the fifth generation of computers, with new advances in ultra$-$small systems, called nanotechnology, and artificial intelligence. $(16)$ Fifth$-$generation inventors are focusing on giving computers human language recognition and the ability to learn and to organize information by themselves. $(17)$ One can only guess$$or fear$$what might be just a few generations away. $(18)$ Computers of the future may help us solve massive problems of human hunger, disease, and poverty. $(19)$ Or perhaps we will create a humanoid robot army stronger and smarter than we are that will revolt and enslave us$.$

QuestionD$7.$ In general, the major supporting details of this paragraph are

a$.$ statistics concerning how fast different computers can process information.

b$.$ ways in which computers have helped us solve problems.

c$.$ distinct generations of computers.