Which optimal background mechanism do you use to retrieve the top 10 buyers from the following options?

An e-commerce site deals with multiple orders daily. The site wants to provide discounts for the top customers based on the purchase amount in the previous month. On the last day of every month, top buyers are identified based on the purchase amount and the discounts are applied on the first item purchased in the next month.

Which optimal background mechanism do you use to retrieve the top 10 buyers from the following options?
A . Advanced agent
B . File listener
C . Job scheduler
D . Queue processor

Answer: C