successor and feasible successor

I know that only successor routes appear in the routing table, but how can I tell the difference between successor and feasible successor?

R1# show ip eigrp topology
IP-EIGRP Topology Table for AS(1)/ID(172.31.16.1)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 172.31.151.0/24, 1 successors, FD is 768
via Connected, Loopback1
P 172.31.211.0/24, 1 successors, FD is 1024
via 172.31.11.201 (1024/76, FastEthernet0/0
P 172.31.24.0/30, 1 successors, FD is 768
via 172.31.11.2 (768/512), FastEthernet0/0
via 172.31.14.2 (1024/512), Serial0/0.4


======================================


P 172.31.24.0/30, 1 successors, FD is 768
via 172.31.11.2 (FD768/AD512), FastEthernet0/0
via 172.31.14.2 (FD1024/AD512), Serial0/0.4