How exactly does "Number of products replaced with a new product" qualify as a cost driver?

Linda Doody is examining customer-service costs in the southern region of Clancey Products Clancey Products has more than 200 separate electrical products that are sold with a 6-month guarantee of full repair or replac sement with a new product. When a product is returned by a customer, a service report is prepared. This service report includes details of the problem and the time and cost of resolving the problem. Weekly data for the most recent 8-week period are as follows Requirement 3. What variables, in addition to number of service reports, might be cost drivers of weekly customer-service costs of Clancey Products? Select two variables that might be cost drivers of weekly customer-service costs of Clancey Products Number of products repaired and the time and cost of repairs. Number of products replaced with a new product._ $21 $21 20 20 17 $17 16 16 15 14 14 13, 13 12, $12 10 10 0 50 100 150 200 250 300 350 400 450 500 Number of service reports