Comprehensive and Detailed Explanation: Aload balanceris designed todistribute user requestsacross multiple servers toensure high availability and performance. Breakdown of Options: * A. Router- Directs trafficbetween networks,not between web servers. * B. Switch- Works atLayer 2, doesnot distribute web traffic. * C. Firewall- Secures network traffic, butdoes not distribute load. * D. Load balancer-#Correct answer.Optimizes web traffic distributionacross multiple servers.