Final answer:
In the FQDN 'www.example.com', the domain name is represented by 'example.com'. This includes both the second-level domain 'example' and the top-level domain 'com'.
Step-by-step explanation:
The Fully Qualified Domain Name (FQDN) represents the complete domain name for a specific computer, or host, on the Internet. The FQDN consists of two parts: the hostname and the domain name. In the case of 'www.example.com', 'example.com' represents the domain name. The 'www' is the hostname which represents a machine name within the domain; 'example' is the second-level domain; and 'com' is the top-level domain (TLD).
Therefore, when looking at the FQDN, the part that signifies the domain name is 'd) example.com'.