What is a subdomain and give an example?

• A. A subdomain is a domain that is part of a larger domain (e.g., blog.example.com; "blog" is a subdomain of "example.com").
• B. A subdomain is a completely separate domain on a different top-level domain.
• C. A subdomain is the same as the root domain.
• D. A subdomain is an IP address associated with a domain.

Answer: (A)

A subdomain is a smaller domain that sits under a larger one in the domain name system. It’s created by adding a label on the left side of the main domain, forming a name like blog.example.com. Here, blog is the subdomain, example.com is the main domain, and .com is the top-level domain. Subdomains are useful for organizing different parts of a site or service under the same domain—for example, a blog on blog.example.com can be managed separately from the main site while still belonging to the same domain. DNS records can direct the subdomain to a specific server or IP, using A or CNAME records. This isn’t a completely separate domain on a different TLD, it isn’t the root domain, and it isn’t an IP address.