UNIT 8 $6,860 ($9,800 X .70) COST OF NEXT 7 UNITS = (8 X $6,860...

255. Correct answer c. Viruses are computer programs that propagate themselves from one

computer to another without the user’s knowledge. Trojan horses are restricted to a specific

computer, these are voluntarily installed as regular programs, but, behind the scenes, they

contain codes that a hacker can activate later to take over the computer .