This value is a:

The IP protocol was designed for use on a wide variety of transmission links. Although the
maximum length of an IP datagram is 64K, most transmission links enforce a smaller
maximum packet length limit, called a MTU. The value of the MTU depends on the type of
the transmission link. The design of IP accommodates MTU differences by allowing routers
to fragment IP datagrams as necessary. The receiving station is responsible for
reassembling the fragments back into the original full size IP datagram. IP fragmentation
involves breaking a datagram into a number of pieces that can be reassembled later. The IP
source, destination, identification, total length, and fragment offset fields in the IP header,
are used for IP fragmentation and reassembly.

The fragment offset is 13 bits and indicates where a fragment belongs in the original IP
datagram. This value is a:

A.
Multiple of four bytes

B.
Multiple of two bytes

C.
Multiple of eight bytes

D.
Multiple of six bytes

Explanation:

Reference:
http://www.freesoft.org/CIE/Course/Section3/7.htm(fragment offset: 13 bits)