Final answer:
A Layer 3 device performs the ANDing process on a destination IP address and a subnet mask to determine the network address of the destination network, which assists in correctly routing packets.
Step-by-step explanation:
The ANDing process used by a Layer 3 device is significant for determining the network address of a destination network. When the destination IP address is combined with the subnet mask through a bitwise AND operation the result is the network address. This process is crucial for the device to route packets accurately. If the destination IP address is 192.168.1.10 and the subnet mask is 255.255.255.0, the ANDing process yields the network address 192.168.1.0.
To route a packet to the correct subnet a Layer 3 device such as a router, must first identify the network portion of the IP address. This is achieved through ANDing. It checks whether the destination network is otherwise reachable via its routing table. Therefore the correct answer to the student's question is: d) to identify the network address of the destination network, which is a fundamental step in packet routing.