Which component of a URL is optional?

Which component of a URL is optional?

• A. Fragment
• B. Scheme
• C. Port
• D. Host

Answer: (C)

Understanding which parts of a URL can be omitted helps you see how web addresses identify resources without extra details. The port portion is optional because you can leave it out and the system will use the default port for the chosen scheme. For example, http URLs assume port 80 unless you specify otherwise, and https URLs assume port 443. So http://example.com/path and http://example.com:8080/path both work—the first uses the standard port, the second explicitly specifies a different one. If you don’t need a nonstandard port, you can omit it. Other parts aren’t optional in the same way for a fully qualified URL: the scheme (http, https, etc.) and the host are required to identify where to fetch the resource, while the fragment after a # is optional and only used to point to a part of the resource.

Understanding which parts of a URL can be omitted helps you see how web addresses identify resources without extra details.

The port portion is optional because you can leave it out and the system will use the default port for the chosen scheme. For example, http URLs assume port 80 unless you specify otherwise, and https URLs assume port 443. So http://example.com/path and http://example.com:8080/path both work—the first uses the standard port, the second explicitly specifies a different one. If you don’t need a nonstandard port, you can omit it.

Other parts aren’t optional in the same way for a fully qualified URL: the scheme (http, https, etc.) and the host are required to identify where to fetch the resource, while the fragment after a # is optional and only used to point to a part of the resource.