A .  a technique used in best-effort delivery system to avoid endlessly looping packets.

B .  a technique used by protocols in which a lower level protocol accepts a message from a higher level protocol and places it in the data portion of the low level frame

C .  One of the pieces that results when an IP gateway divides an IP datagram into smaller pieces for transmission across a network that cannot handle the original datagram size.

D .  All of the above

E .  None of the above