You have set up an e$-$mail server that needs to respond to e$-$mail requests by using

mail.coolgadgets.com and

mail.niftytools.com in the request URL. How can you do this?

a$.$ Install two NICs, and assign the same IP address to both NICs. Configure DNS to

map one MAC address to

mail.coolgadgets.com and the other MAC address to

mail.niftytools.com.

b$.$ Configure two IP addresses on one NIC. Configure DNS to map one IP address to

mail.coolgadgets.com and the other IP address to

mail.niftytools.com.

c$.$ Install two NICs, and connect each one to a different network. Set up the router on

each network to forward mail packets to the NIC bound to the correct URL.

d$.$ Install two NICs, and assign different IP addresses to each NIC, but make sure both

IP addresses use the same network ID$.$ Configure the NICs to use default gateways

on different networks.