When designing external interfaces, several considerations must be taken into account:A. Volatility of neighbouring systems - Changes in neighboring systems can affect the stability and compatibility of interfaces, requiring interfaces to be adaptable to changes.C. Protocols enforced by neighbouring systems - It's crucial to align with the protocols used by neighboring systems to ensure seamless communication and interoperability.D. Expected amount of parallel calls - This affects the scalability and performance requirements of the interface, as it must be designed to handle the expected load efficiently.