Which three statements are true about EIGRP route summarization? (Choose three.)

A.
When manual summarization is configured, the router immediately creates a route that
points to null0 interface.

B.
Manual route summarization is configured in router configuration mode when the router is
configured for EIGRP routing.

C.
Manual route summarization is configured on the interface.

D.
The ip summary-address eigrp command generates a default route with an administrative
distance of 5.

E.
When manual summarization is configured, the summary route will use the metric of the
largest specific metric of the summary routes.

F.
The ip summary-address eigrp command generates a default route with an administrative
distance of 90.

Explanation:
The purpose of route summarization is small routing tables, smaller updates. On major
network boundaries, subnetworks are summarized to a single classful network and
automatic route summarization is enabled by default. Manual route summarization can be
configured on per interface basis. When summarization is configured on an interface, the
router immediately creates a route pointing to null0.
Route summarization works in conjunction with the ip summary-address eigrp interface
configuration command, in which additional summarization can be performed. If automatic
summarization is in effect, there usually is no need to configure network level summaries
using the ip summary-address eigrp command. You can configure a summary aggregate
address for a specified interface. If there are any more specific routes in the routing table,
EIGRP will advertise the summary address out the interface with a metric equal to the
minimum of all more specific routes.
http://www.cisco.com/en/US/docs/ios/12_0/np1/configuration/guide/1ceigrp.html