The correct answer is 'Perform the scan during off-peak hours.' Performing vulnerability scans during off-peak hours is a common practice to prevent performance degradation and service disruption, especially in networks with critical real-time processing systems where high availability is a must. Scheduled scans allow analysts to avoid peak traffic times, thus minimizing the impact on network and system performance. Conversely, scanning continuously at a slow pace can still affect performance, scanning during peak hours is likely to cause disruption, and once a year would not provide timely security data. Choosing to never scan is not an option for maintaining security posture.