The Database Resource Manager is automatically enabled in the maintenance window that runs the Automated Maintenance Task. What is the reason for this？（）

A. to prevent the creation of an excessive number of scheduler job classes
B. to allow the Automated Maintenance Tasks to use system resources without any restriction
C. to allow resource sharing only among the Automated Maintenance Tasks in the maintenance window
D. to prevent the Automated Maintenance Tasks from consuming excessive amounts of system resource