Story points are a relative estimation unit, not a direct representation of elapsed hours. They allow the Scrum Team to compare the overall size of User Stories by considering characteristics such as effort, complexity, uncertainty, and risk.
SCRUMstudy states that Relative Sizing/Story Points assigns a point value according to the overall size of a User Story, considering factors including the effort required and level of complexity. Once one item has been estimated, other User Stories can be estimated relative to that reference item.
Option A incorrectly equates story points with hours. Scrum can use time-based task estimates, but story points intentionally support relative rather than absolute estimation. Option C describes a count of completed stories rather than story points. Option D incorrectly assigns estimation responsibility to the Product Owner. Estimation is performed by the Scrum Team, because those performing the work are best positioned to judge its technical complexity and effort.
Story points consequently support velocity measurement and future forecasting without pretending that complex knowledge work can always be predicted precisely in hours.
Study Guide reference: Plan and Estimate - > Estimate User Stories - > Relative Sizing/Story Points.
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