Which of the following refers to the smallest increment of work in Agile?

The term that refers to the smallest increment of work in Agile is a "Story." In Agile methodologies, particularly in frameworks like Scrum, a Story is a unit of work that represents a requirement or user need expressed from the end-user's perspective. It typically captures a specific need along with the value it delivers, and is designed to be completed within a single iteration or sprint.

Stories are small enough to be manageable and help teams focus on delivering incremental value to the customer. Each story is usually accompanied by acceptance criteria that define what needs to be done in order for the work to be considered complete.

In contrast, an Epic is a larger body of work that can be broken down into multiple Stories, making it a higher-level aggregation of functionality. A Feature refers to a collection of related Stories that deliver a significant piece of functionality. Tasks, on the other hand, are specific actions or work items that are needed to complete a Story but are generally considered a lower level of granularity compared to Stories themselves.

By defining work in terms of Stories, Agile teams can prioritize and deliver value more effectively and ensure that they remain aligned with customer needs throughout the development process.