The correct answer is To monitor progress for a defined set of related issues and pull requests toward a goal date.

A milestone in GitHub groups issues and pull requests under a single target so the team can track how many items are open or closed and work toward a due date. This fits a 90 day release plan because the milestone provides a time bound container with progress indicators and filtering that keep related work aligned to the scheduled release.

To organize issues and pull requests by topic using labels is not the primary purpose in this scenario because categorizing by topic does not provide a goal date or an aggregate progress view for a release.

To measure how many lines of code each contributor commits is unrelated because milestones do not track individual contribution metrics and lines of code are not a reliable measure of progress.

To limit access to selected repository features is incorrect because access control is managed through repository permissions and settings rather than milestones.

Full AWS Practitioner Certification Question