Correct Answer: A
Explanation:
To run Automation documents on a schedule in AWS Systems Manager, a maintenance window must be configured. Maintenance windows define the time periods during which automated tasks, including the execution of Automation documents, can run. The WGU Cloud Deployment and Operations Study Guide (Section 5.2, Maintenance Windows) explains that maintenance windows are used to schedule and control the execution of Systems Manager tasks, ensuring they align with operational windows. Rate control, session preferences, and resource groups are not used for scheduling automation tasks.