Which IPv4 addressing and routing scheme can increase the availability of a network service during a DoS attack?

Unicast maps one IP address to one specific host, making a single server the sole target of all DoS traffic with no inherent distribution or redundancy.

Broadcast sends packets to all hosts on a subnet and is not used for service delivery - it is not applicable to mitigating DoS attacks against a specific network service.

Anycast allows multiple hosts to share a single IP address, and routing directs each client to the topologically nearest instance - during a DoS attack, volumetric traffic is distributed across many servers and network paths rather than overwhelming a single destination, significantly increasing service availability and resilience.

Multicast delivers packets to a subscribed group of receivers but is designed for one-to-many content distribution, not for distributing inbound service requests or absorbing DoS attack traffic across server instances.