The IS auditor's primary concern when an organization has recently implemented a Voice-over IP (VoIP) communication system is a single point of failure for both voice and data communications. VoIP is a technology that allows voice communication over IP networks such as the internet. VoIP can offer benefits such as lower costs, higher flexibility, and better integration with other applications. However, VoIP also introduces risks such as dependency on network availability, performance, and security. If both voice and data communications share the same network infrastructure and devices, then a single point of failure can affect both services simultaneously and cause significant disruption to business operations. Therefore, the IS auditor should evaluate the availability and redundancy of the network components and devices that support VoIP communication. The other options are not as critical as a single point of failure for both voice and data communications, as they do not pose a direct threat to business continuity. References: CISA Review Manual,
27th Edition, page 385