Two routers named Atlanta and Brevard are connected via their serial interfaces as illustrated, but they are unable to communicate. The Atlanta router is known to have the correct configuration.Given the partial configurations, identify the fault on the Brevard router that is causing the lack of connectivity？（）

• A、incompatible IP address
• B、insufficient bandwidth
• C、incorrect subnet mask
• D、incompatible encapsulation
• E、link reliability too low
• F、IP/TCP closed