When closing a project, which of the following must be completed to allow team members to return to their designated departments?

A retrospective captures lessons learned for future improvement but does not formally return team members to their departments.

Releasing resources is a required project closure activity that formally ends team members' allocation to the project, allowing them to be reassigned to their functional departments or other work. Without this step, team members remain tied to the project in resource management systems and cannot be officially returned. This activity directly addresses the scenario's requirement of returning people to their designated departments.

Obtaining sponsor sign-off confirms formal project acceptance and completion but does not itself release team members back to their home departments.

Closing contracts pertains to vendor and procurement agreements, not to the reassignment of internal team members.