* Routing Table and Equal-Cost Routes:When multiple routes to the same destination network have the same cost (e.g., metric or administrative distance), they are referred to as "equal-cost routes." Routers use load balancing to distribute traffic across these routes.
* Analysis of Options:
* Option A: "Sub-optimal routes" are routes that are not preferred due to higher cost or less desirable metrics.
* Option B: "Multipath routes" is a general term but does not specify equal cost, making it less precise.
* Option C: "Equal-cost routes" is correct as the scenario specifies the same destination network with the same cost.
* Option D: "Default routes" are used when no specific route matches the destination, which is unrelated to the given scenario.
* Correct answer:The routes are C (Equal-cost routes).

Comprehensive Explanation: A routing table contains several key elements:
* Cost: Also known as metric, this indicates the cost associated with reaching a specific destination, such as the number of hops or link speed.
* Next-hop address: This is the IP address of the next device along the route that packets should be forwarded to.
* Protocol: The routing protocol (e.g., OSPF, RIP) that determined the route.
* Interface: The physical or logical interface through which the router sends packets to reach the destination.
* Destination/Mask: The destination network or subnet and the associated subnet mask define the range of IP addresses for which this route is valid. These elements together allow routers to efficiently forward traffic to the correct destinations.

Detailed Explanation:The Priority Code Point (PCP) field in an 802.1Q VLAN tag is 3 bits long, which gives it a value range of 0 to 7. This field is used to indicate the priority of the frame, with higher values indicating higher priority.

Comprehensive Explanation: In Spanning Tree Protocol (STP), the Message Age in the BPDU (Bridge Protocol Data Unit) sent by the root bridge is set to 0. As BPDUs are forwarded by non-root switches, the Message Age is incremented. This timer is used to ensure that outdated information is not propagated indefinitely through the network. If the Message Age reaches a configured maximum value, the BPDU is discarded, and the network topology is recalculated.

When HostA wants to send data to HostC, the following steps occur:
* HostA checks if HostC is in the same subnet:
* HostA and HostC are in different network segments, meaning HostA must send the packet to its default gateway (RTA, G0/0/0) to reach HostC.
* HostA needs the MAC address of its gateway (RTA G0/0/0):
* Since ARP (Address Resolution Protocol) is used to resolve IP to MAC addresses, HostA will send an ARP Request to obtain the MAC address of G0/0/0 of RTA.
* RTA forwards the packet to HostC:
* Once HostA sends the packet to RTA (using G0/0/0's MAC), RTA will route it to the correct network segment and send it to HostC through G0/0/1.
Why the Other Options Are Incorrect:
* Option A (HostC) - Incorrect:
* HostA does not send an ARP request for HostC because HostC is in a different subnet.
* Option B (G0/0/1 of RTA) - Incorrect:
* HostA only communicates with its directly connected gateway (G0/0/0), not G0/0/1.
* Option C (SWA) - Incorrect:
* Switches (SWA, SWB) operate at Layer 2 and do not require ARP.
Final Answer: D (G0/0/0 of RTA)