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.