Multicast is the network communication method to use when audio transmissions need to reach several specific devices simultaneously over an IP network. It allows for efficient network use by directing a single stream of data to multiple recipients without needing to send separate streams to each recipient. Unicast sends data to a single destination, anycast sends data to the nearest or best destination in a group, and broadcast sends data to all devices in the network segment. Thus, multicast is most appropriate for the requirement described.

Cameras are the best tool for remotely monitoring who is accessing a secure data center. They provide real-time visual verification of individuals entering and exiting the facility and can be monitored remotely to ensure security protocols are followed. Access control vestibules, employee training, and biometrics are also important for security but do not offer the same continuous, visual monitoring capability that cameras do. Cameras also serve as a deterrent to unauthorized access and can provide forensic evidence in the event of a security breach.

The most likely reason an insurance brokerage would enforce VPN usage is to encrypt sensitive data in transit.
A VPN (Virtual Private Network) is a technology that creates a secure and encrypted tunnel between two or more devices over a public network, such as the internet. A VPN allows users to access remote resources or services as if they were on the same private network, while protecting their data from interception, modification, or spoofing by malicious actors. An insurance brokerage would use a VPN to protect the confidentiality and integrity of sensitive data, such as customer information, financial records, or insurance policies, that are transmitted over the internet. References: CompTIA Network+ N10-008 Certification Study Guide, page 403; The Official CompTIA Network+ Student Guide (Exam N10-008), page 15-5.

Explanation
Decreasing the lease duration on the DHCP server will cause clients to renew their IP address leases more frequently, freeing up IP addresses for other clients to use. References: CompTIA Network+ Certification Study Guide, Chapter 3: IP Addressing.