Final answer:
option C. Router. A router by default does not forward any broadcast or multicast packets because it is meant to route packets between different networks and such traffic is generally confined to a single local network.
Step-by-step explanation:
The device that by default does not forward any broadcast or multicast packets is a router. Routers are designed to send packets between different networks, and by default, they do not forward broadcast or multicast traffic that is directed to all devices on a network.
This behavior is due to the fact that these types of traffic are typically meant to stay within a single broadcast domain or local network. In contrast, a repeater simply amplifies signals, a hub forwards packets to all ports, and a switch forwards broadcast and multicast to all ports but can also limit traffic with configuration.
The device that, by default, does not forward any broadcast or multicast packets is C. Router. Routers operate at the network layer (Layer 3) of the OSI model and are designed to separate broadcast domains. Unlike hubs and switches, routers do not forward broadcast packets beyond the local network; instead, they route packets based on destination IP addresses.
Routers create network boundaries, preventing broadcast and multicast traffic from spreading across different subnets. Hubs (B) and switches (D) operate at lower layers and typically forward broadcast traffic within the same network segment. A repeater (A) amplifies signals but does not perform packet filtering.