Which type of EIGRP route entry describes a feasible successor?

A.
a backup route, stored in the routing table

B.
a primary route, stored in the routing table

C.
a backup route, stored in the topology table

D.
a primary route, stored in the topology table

Explanation:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093f07.shtml
Feasible Successors A destination entry is moved from the topology table to the routing table when
there is a feasible successor. All minimum cost paths to the destination form a set. From this set, the
neighbors that have an advertised metric less than the current routing table metric are considered
feasible successors. Feasible successors are viewed by a router as neighbors that are downstream

with respect to the destination. These neighbors and the associated metrics are placed in the
forwarding table. When a neighbor changes the metric it has been advertising or a topology change
occurs in the network, the set of feasible successors may have to be re-evaluated. However, this is
not categorized as a route recomputation. Feasible successor is a route whose Advertised Distance
(AD) is less than the Feasible Distance (FD) of the current best path. A feasible successor is a backup
route, which is not stored in the routing table but, stored in the topology table.