正解:B
Clustering is a technique that allows multiple servers to work together as a single system, providing high availability, load balancing, and fault tolerance. Clustering can limit the potential impact of server failures in a distributed environment, as it can automatically switch the workload to another server in the cluster if one server fails, without interrupting the service. Redundant pathways, failover power, and parallel testing are also useful for improving the reliability and availability of servers, but they do not directly address the issue of server failures.