Which three statements are true about EIGRP operation?（）

• A、When summarization is configured, the router will also create a route to null 0.
• B、The summary route remains in the route table, even if there are no more specific routes to the network.
• C、Summarization is configured on a per- interface level.
• D、The maximum metric for the specific routes is used as the metric for the summary route.
• E、Automatic summarization across major network boundaries  is enabled by default.