Default gateway is the point of access through which information is sent from source to reach the destination in a network though computer towards different network.
It provides destination to all the traffic on the network as default when route data packets don't match with the IP address .
Other options are incorrect because subnet mask is masking technique for splitting it into the network address and host address.Domain Name Servers (DNS) is the system for naming in network. IP address is the internet protocol address.
