Hilary has been working on a pilot project for a start$-$up on which she has been testing the maximum bytes for the length of an IP packet. As her intended IP packets are larger than what the network allows, she has to break them up into smaller packets for transmission. Analyze and suggest which of the following fields Hilary should use in an IPv$4$ packet so that the receiving host is able to identify and reassemble the fragmented messages.

a$.$ Fragment offset

b$.$ Identification

c$.$ Version

d$.$ Flags