Final answer:
The likelihood of port scans against systems in a small, regional business's DMZ is high. The correct option is c.
Step-by-step explanation:
Alex should consider that the likelihood of port scans occurring against systems in her organization's DMZ is high. Port scans are a common preliminary activity for attackers seeking to identify services they can exploit. Moreover, given that the DMZ hosts services meant to be available to external users, it is an attractive target for reconnaissance activities. Port scanning is generally low-cost and low-risk for attackers, adding to the rationale that most exposed systems are likely to be scanned at some point.
However, the absolute likelihood can vary based on several other factors such as the visibility of her organization on the internet, the industry sector, and known vulnerabilities in the services hosted in the DMZ. It's also worth noting that automated scans by bots are very common, and so any system connected to the internet, particularly in a DMZ, is likely to be probed. The best practice for Alex would be to assume a proactive stance with strong security measures in place to detect and mitigate such scans.