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.