In EIGRP, which of the following metrics is used to determine the best path to a destination?

All of the listed metrics—delay, reliability, and load—are employed in the EIGRP (Enhanced Interior Gateway Routing Protocol) metric calculation to determine the best path to a destination. EIGRP utilizes a composite metric, which incorporates multiple attributes to provide a more comprehensive evaluation of the network's conditions.

Delay is a measure of the time it takes for packets to traverse the path. Longer delays typically indicate less favorable paths, as they can lead to increased latency in data transmission.

Reliability reflects the error rate on the path, indicating how often packets are dropped or need to be retransmitted. A highly reliable path is preferred, as it ensures that data integrity is maintained and minimizes the chances of delay incurred due to retransmissions.

Load is a measure of how much traffic is currently utilizing a path. Paths with a higher load are considered less desirable because they may become congested, leading to degradation in performance and increased delays.

By considering all these factors together, EIGRP can make informed routing decisions to select the most efficient and stable path for data to travel through, ensuring optimal network performance. This comprehensive approach is what distinguishes EIGRP's metric system from those of other routing protocols that may only consider one or two of these parameters.