The correct answer is A because the Coverage Rules tab within the Enrollment Event Rule is where Workday defines how elections are defaulted when an employee does not take action during a benefit event. This includes scenarios such as overdue events that are finalized using the Finalize Open Benefit Events process. The system uses the defaulting logic configured in this tab---such as ''Default to Current Elections or Waive''---to determine whether existing elections are carried forward or coverage is waived.

Option B is incorrect because the Enrollment Event Type defines the nature of the event and triggering conditions, but it does not control election defaulting behavior. Option C is also incorrect because the Loss of Coverage tab is used to manage coverage termination scenarios, not default election outcomes. Option D is incorrect because benefit plan configuration defines plan-specific details but does not control how elections default when no action is taken during an event. Therefore, to manage how Workday assigns elections when events are closed without employee input, the configuration must be set on the Coverage Rules tab of the Enrollment Event Rule.