Refer to the following.
Router # sh ip route eigrp
13.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D 13.0.0.0/8 is a summary, 00:00:32, Null0
What happens to packets that are forwarded from the 13.0.0.0/8 network to the Null0
interface?

A.
Flagged

B.
Accepted

C.
Summarized

D.
Dropped

Explanation:
When an EIGRP router summarizes, it automatically builds a route to null0 for the
summarized route. The router to null0 prevents packets that do not match a specific entry in
the routing table from following a default route. (The route to null0 causes the packet to be
dropped).