Which of the following is used to redistribute traffic between one source and multiple servers...

The correct answer is Load balancer because it is specifically designed to distribute incoming network traffic across multiple backend servers that provide the same application or service. According to CompTIA Network+ (N10-009) objectives under network infrastructure, load balancing improves performance, scalability, and high availability by preventing any single server from becoming overwhelmed.

A load balancer can operate at Layer 4 (transport layer, based on IP address and port) or Layer 7 (application layer, based on content such as HTTP headers or URLs). It uses various algorithms such as round-robin, least connections, or weighted distribution to efficiently allocate client requests among servers. If one server fails, the load balancer can redirect traffic to healthy servers, ensuring service continuity.

A router (Option A) forwards packets between different networks but does not distribute traffic among servers running the same application. A switch (Option B) forwards frames within a local network based on MAC addresses. A firewall (Option C) filters traffic based on security rules but does not perform traffic distribution for load-sharing purposes.

Therefore, a load balancer is the correct solution for redistributing traffic among multiple servers.