Which option describes the scalability advantage of a 3-tier network design?

The 3-tier network design is particularly advantageous in terms of scalability because it effectively separates different layers of network functionality into distinct tiers: access, aggregation, and core.

In a 3-tier architecture, each tier can be scaled independently based on the specific needs of the organization. For instance, if an organization requires more user access points, additional access switches can be added without significantly impacting the aggregation or core layers. This modular approach allows for a gradual expansion of the network as demands grow, which enhances the overall scalability.

Moreover, with the distinction of roles among the tiers, there's more flexibility in adding resources or optimizing bandwidth, which is often necessary as a network grows. This contrasts with the 2-tier design, where the lack of level differentiation can create bottlenecks and complicate scaling efforts, especially as the number of devices and users increases.

By enabling independent scaling and more efficient resource utilization, the 3-tier model offers a distinct advantage when compared to simpler configurations.