In a packet switching network, packets are routed from source to destination along a single path having two intermediate nodes. If the message size is 24 bytes and each packet contains a header of 3 bytes, then the optimum packet size is

With 2 intermediate nodes, there are 3 hops. Total overhead is 3 hops * 3 bytes = 9 bytes per packet. To minimize overhead while fitting the 24-byte message, we calculate efficiency; however, in many textbook problems of this type, the packet size is often constrained by the header or specific framing logic. Given the options, 9 is the only one that allows for a balanced division of the message.