Explanation:

The history of personal computer viruses began in the early 1980s with various experimental and 'in-the-wild' programs. **Analysis of Options:** * The first known virus to spread 'in the wild' for Apple II systems was 'Elk Cloner', created in 1982. * For IBM PC compatible computers, the first widely known virus was 'Brain', which appeared in 1986. * **Option (A) 1980:** Incorrect. There is no widely recognized PC virus that emerged in 1980. * **Option (B) 1984:** Incorrect. While some early forms of malicious code or experimental programs might have existed, no significant PC virus outbreak or widely recognized virus development is attributed to this year. * **Option (C) 1986:** Correct. The 'Brain' virus, developed by two brothers in Pakistan, is widely considered the first IBM PC compatible virus. It was a boot sector virus that spread via floppy disks. Given the options, 1986 is the most accurate answer for the development of a significant 'PC virus'. * **Option (D) 1988:** Incorrect. This year saw the emergence of more sophisticated viruses and wider outbreaks, such as the Morris Worm (though not strictly a PC virus, it affected many systems), but not the development of the *first* PC virus.