Which of the following provides services with a single purpose or function?

Directory Services are specifically designed to provide a single function: managing and providing access to a set of directory data within a network. This encompasses the storage of user and resource information, authentication, and access control, facilitating efficient and centralized management of users, devices, and applications. Directory Services like Active Directory or LDAP serve as a fundamental component in many organizational infrastructures, ensuring that resources are easily located and accessed by authorized entities.

In contrast, an Enterprise Service Bus is a middleware solution that enables different applications to communicate with one another, facilitating integration across various services and systems rather than supporting a single function. Service-Oriented Architecture, as a broader framework, focuses on the design and implementation of software services, often involving multiple functionalities and interactions among services, which further differentiates it from a single-purpose entity. Data Life Cycle management pertains to the handling of data through various stages of its existence and is about more than just a single function or service.