Which statement best describes hierarchical addressing in IPv4?

• A. It improves routing efficiency by reducing router state.
• B. It complicates routing tables.
• C. It has no effect on routing.
• D. It only applies to IPv6.

Answer: (A)

Hierarchical addressing in IPv4 refers to organizing addresses so that prefixes represent networks and the remaining bits identify hosts, enabling route aggregation. With this structure, routers can summarize many subnets into a single route, reducing the number of entries in their forwarding tables. That simplification makes routing faster and more scalable because less router state needs to be stored and exchanged. So the statement that it improves routing efficiency by reducing router state is the best description. It does affect routing—it's not that it has no effect—and it isn’t limited to IPv6; IPv4 uses hierarchical addressing through CIDR as well.