Dynamic routing protocols are designed to automatically discover network paths and adapt to topology changes in real-time. When a router or link fails, these protocols recalculate and propagate new, optimal routes without requiring manual administrator intervention. This makes them ideal for large, complex networks.

Conversely, static routing involves manually configuring each route on every router. This approach is simple and consumes minimal CPU and memory resources, as no complex algorithms are running. However, its lack of automatic adaptation makes it suitable only for small, predictable networks where the topology is stable and changes are infrequent.

A. Static routing has very low resource overhead. Dynamic routing protocols are the ones that consume significant CPU and memory to run their algorithms and maintain state tables.

B. The primary purpose of dynamic routing protocols is to automate the maintenance of routing tables, eliminating the need for periodic manual updates by an administrator.

E. While dynamic routing automates route discovery, it still requires significant initial configuration by an administrator to enable the protocol, define its parameters, and select which networks to advertise.

1. Kurose, J. F., & Ross, K. W. (2021). Computer Networking: A Top-Down Approach (8th ed.). Pearson. In Section 5.2, "Routing Algorithms," the text distinguishes between static and dynamic approaches, stating, "With dynamic routing algorithms, the routing paths change as the network traffic loads or topology change," which supports option C. It also notes that static routing is used "in small networks," supporting option D.

2. Cisco. (2023). IP Routing: Static and Dynamic Routes. Cisco Press. In the "Static Routing" section, it is noted that "Static routing has low overhead" and is "useful for small networks." The "Dynamic Routing" section explains that these protocols "automatically adjust to topology or traffic changes," directly validating answers D and C, respectively, and invalidating A.

3. Forin, A., & Poutievski, L. (2011). Lecture 15: Routing. MIT OpenCourseWare, 6.02 Introduction to EECS II: Digital Communication Systems, Spring 2011. The lecture notes explain that static routing is "simple" but "brittle" to changes, making it suitable for stable environments (supporting D). In contrast, dynamic routing is described as "adaptive" to network changes (supporting C).