Final answer:
Namespaces in XML allow organizations to specify globally unique names as element tags in documents.
The Correct Option is; (d) Namespace.
Step-by-step explanation:
The mechanism in XML that allows organizations to specify globally unique names as element tags in documents is Namespace.
Namespaces in XML provide a way to avoid naming conflicts by assigning a unique identifier to each element or attribute. This allows different organizations to use their own custom tags without worrying about name collisions.
For example, consider two organizations, A and B, both using XML to represent their data. Organization A might use the tag <A:customer> to represent a customer, while Organization B might use the tag <B:customer>.
Both organizations can define their own namespaces, A and B, respectively, to ensure that their tags do not conflict with each other.