Which system categorizes resources by purpose, owner, or environment using key-value pairs?

The correct answer is associated with how resources are organized and identified in modern technological environments. Tagging systems utilize key-value pairs to assign attributes to various resources, thereby facilitating easier management, retrieval, and filtering of information based on specific criteria.

By using tags, an organization can categorize resources according to different attributes, such as the purpose of the resource (e.g., development, testing, production), the owner (who is responsible for the resource), or the environment (such as cloud, on-premises, or hybrid). This method enhances organization and can support various tagging strategies, making it simpler for users to locate and manage resources efficiently.

In contrast, other choices do not fit this definition as closely. Provision refers to the process of allocating resources, which does not inherently involve categorization through key-value pairs. Middleware acts as a bridge between different applications and does not serve a primary role in resource identification through tags. Metadata, while it describes data and can include key-value pairs, is more about providing information about the data itself rather than categorizing resources in a structured manner like tagging does. Therefore, tagging is specifically designed for resource categorization using key-value pairs, making it the most suitable answer.