A.Packets to the IP address 10.10.10.5/32 will be tagged with "17" toward the next hop.
B.Label "19" will be advertised to MPLS neighbors so that they can use this label to reach the IP address 10.10.10.6/32.
C.IP address 10.10.10.4/32 is directly connected to the neighbor router on serial 3/0.
D.Packets arriving with label "17" will be forwarded without any label toward serial 4/0.
E.Packets arriving with label "20" will be forwarded with label "21" after label-swapping.
F.Label "20" is advertised to MPLS neighbors so that they can use this information to reach the prefix 10.10.10.8/32.