Detailed Answer
(c) The requirement is to identify the operating procedure
most likely to increase an organization’s exposure to computer
viruses. Answer (c) is correct because there is a risk that
downloaded public-domain software may be contaminated with
a virus. Answers (a) and (b) are incorrect because viruses are
spread through the distribution of computer programs. Answer
(d) is incorrect because original copies of purchased software
should be virus-free and cannot legally be shared.