The network topology is a ring, which inherently provides two link-disjoint paths between any two nodes. The displayed routing shows one of these paths being used for each demand (the working path). For example, the demand from A to C uses the path A-B-C. A second, disjoint path, A-E-D-C, is available on the other side of the ring. This structure is the fundamental requirement for implementing 1+1 protection, where a dedicated protection path is available to take over if the working path fails. The design, therefore, supports the 1+1 protection requirement.

B. Minimum cost design: The design is not minimum cost because it forgoes using the more direct "candidate" links (e.g., A-C), opting instead for multi-hop paths around the ring perimeter.

C. Minimum latency: Latency is proportional to distance. Routing around the ring (e.g., A-B-C is 160 km) results in higher latency than a potential direct candidate link would provide.

D. Resilience against two link faults: A simple ring topology is not inherently resilient to two link faults. The failure of two non-adjacent links (e.g., A-B and C-D) would partition the ring into disconnected segments.

1. Nokia Network Services Platform (NSP) 23.10 NFM-P Transport Network Design and Optimization Guide, Chapter: "Optical network design", Section: "Protection and restoration". This guide details protection mechanisms, stating: "1+1 protection provides dedicated protection where a protection path is configured for a specific working path. The working and protection paths are typically disjoint." The ring topology in the exhibit provides this required path disjointness.

2. Pioro, M., & Medhi, D. (2004). Routing, Flow, and Capacity Design in Communication and Computer Networks. Morgan Kaufmann. Chapter 7, "Survivable Network Design". Section 7.2 discusses how 2-connected topologies, such as a ring, can survive any single link failure by rerouting traffic, which is the basis for 1+1 protection. It also clarifies that two link failures can disconnect the network.

3. Nokia Service Routing Architect (SRA) Self-Study Guide: Preparing for the 4A0-200 Exam Series, (Internal Nokia Courseware). The principles of network survivability are covered, emphasizing that ring topologies are a common and simple method to achieve path diversity for protection against single points of failure, but not multiple simultaneous failures.