Which of the following statements about the Fragment Offset field is true?

• A. It tracks the position of a fragment's data within the original packet.
• B. It identifies the fragment uniquely.
• C. It indicates the total number of fragments.
• D. It carries the protocol number.

Answer: (A)

The Fragment Offset field tells where this fragment’s payload starts within the original IP datagram, measured in 8-byte units. This position information is what lets the receiver piece fragments back together in the correct order, even if they arrive out of order. The first fragment has an offset of 0, and multiplying the offset by 8 gives the exact byte position of the fragment’s data in the original packet. The total length of each fragment’s data is given by the Length fields in the header, and the MF (More Fragments) flag indicates whether more fragments follow.

It does not identify a fragment uniquely—that’s the job of the Identification field. It does not indicate the total number of fragments, which isn’t a separate field—reassembly relies on offsets and the MF flag. It also does not carry the protocol number; that information is in the Protocol field of the IP header.