Answer:
d). Argument; conclusion: It's even more important ... protected by a firewall.
Step-by-step explanation:
In the given excerpt, the argument and the conclusion that the author deduces is 'the increased importance of safeguarding your PCs with a firewall.' The argument is logically supported by the proper evidence in order to show the probable threats associated with keeping your computers unprotected('identity theft, fencing stolen Ids, defraud, etc). These factual descriptions substantiate the author's claim and justify his deduction that it is a must to keep your computers safe using a firewall in order to prevent these crimes. Thus, option d is the correct answer.