Question: What is a key characteristic of Northbound APIs utilizing the Common API Framework, to ensure network efficiency and scalability?
Option 1: Stateless design, where each request contains all necessary information for server processing
Option 2: Stateful architecture, allowing servers to retain client session information
Option 3: Mandatory use of custom RPC-style interactions for all service operations
Option 4: Requirement for clients to be aware of server-side API execution aspects
Explanation: A stateless design is crucial for Northbound APIs, as it enables each request to contain all necessary information for the server to process it without needing to retain any client context from previous requests. This approach improves network efficiency by supporting caching and allows for better scalability in telecom networks, aligning with principle 3 outlined in the API design considerations.