Which of the following technique is used for encapsulation?

• A. a technique used in best-effort delivery systems 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