A is the answer to this question. The network address is the first address of the subnet. This is important because this is needed to know details about the source and the destination of the different sub-networks available. The network address is also responsible for allowing the network to be distinguished. Take note that the IP address and the network address are not the same.
The network address is known to be a numerical address that is used to distinguish the network that is being used while the IP address is bound and connected to the network device that is being used. These two should not be interchanged with each other because they are different.