Answer:
B. Server and domain
Step-by-step explanation:
A domain is a pointer to an IP address in which a server resides. It is a unique url for accessing data or files on a server. A server is where actual files are located (or hosted).
A domain can be seen as an address to a particular house and a server is the house itself. To access a work email, the address (domain) to the server hosting the email must be known.
Hope this helps!