How does Router-A forward traffic destined to 172.18.3.5 with four equal-cost paths available?

The correct answer indicates that traffic will be forwarded over the single path installed in the forwarding table. In scenarios where there are equal-cost multi-path (ECMP) routes, the routing protocol typically installs multiple routes into the routing table, and forwarding decisions are made based on the information in that table.

When a router has multiple equal-cost paths to a destination, it has the capability to perform load balancing across the available paths. However, if the forwarding behavior is configured to always use a single path due to certain settings or defaults, or if there is a specific routing policy in place, then traffic will not be split among the multiple available paths.

This approach simplifies the routing decision-making process but may not take full advantage of the redundancy and bandwidth available through the equal-cost paths. In many situations, routers can be configured to utilize load balancing features to make use of all available paths, but if default behavior or specific configurations dictate otherwise, traffic may flow exclusively through one of the equal-cost paths as represented in the forwarding table.

In contrast, other options suggest behaviors that do not align with the fundamental principles of how routing and forwarding work in the context of equal-cost paths. For example, the idea of rotating traffic across paths for a set time or varying forwarding based