As a Sales Promotion Tactic,why Do Marketers Prefer Using Rebates

As a sales promotion tactic,why do marketers prefer using rebates?

A) because they offer incentives that encourage satisfied customers to become repeat customers
B) because customers often fail to redeem them
C) because they are most effective on everyday purchases
D) because they are easy for the customer to use
E) because they offer the customer a chance to actually try the product