Explanation/Reference:
Explanation:
External vulnerability sources are going to be the most cost-effective method of identifying these vulnerabilities. The cost involved in choices B and C would be much higher, especially if performed at regular intervals. Honeypots would not identify all vendor vulnerabilities. In addition, honeypots located in the DMZ can create a security risk if the production network is not well protected from traffic from compromised honey pots.

Explanation
Patches should be applied whenever important security updates are released. They should not be delayed to coincide with other scheduled rollouts or maintenance. Due to the possibility of creating a system outage, they should not be deployed during critical periods of application activity such as month-end or quarter-end closing.

D, perform a cost-benefit analysis.

Section: INFORMATION SECURITY GOVERNANCE