Final answer:
In the agile model, a story point is used to estimate the size of a user story, considering the work involved, the task complexity, and potential risks. It helps in sprint planning and work prioritization.
Step-by-step explanation:
In the agile model, a story point is an estimate of the size of a user story. It is a unit of measure for expressing the overall effort that will be required to fully implement a product backlog item or any other piece of work. Story points take into account the amount of work to do, the complexity of the work, and any risks or unknowns that might impact the progress of the task. Unlike estimating with actual time, story points reflect the relative size of tasks, which can be more consistent across team members with varied skill sets and experience levels.
Story points are used during sprint planning sessions to help prioritize tasks and to determine how much work the team can commit to in the next sprint. For example, if solving a specific issue in software development is estimated as 5 story points, and adding a new feature is estimated as 3 story points, the team might decide to tackle both issues in the next sprint if they've historically completed about 8 story points in a sprint.
Therefore, the correct answer to the student's question is: An estimate of the size of a user story.