Using Oracle Scheduler you have scheduled two jobs， JOB_A and JOB_B， to run at 9：00 p.m. every Friday. You want both the jobs to use a single resource plan， WEEKEND_PLAN. Which task must have already been performed to enable you to achieve this objective？（）

• A、 A window must have been created with the WEEKEND_PLAN resource plan.
• B、 A program must have been created with the WEEKEND_PLAN resource plan.
• C、 A job class must have been created with the WEEKEND_PLAN resource plan.
• D、 A windows group must have been created with the WEEKEND_PLAN resource plan.