Callahan corporation is a wholesaler that sells a single product. Management has provided the following cost data for two levels of monthly sales volume. The company sells that the product for $115.80 per unit. Sales Volumes (units) 4,000 5,000 $338,000 $422,500 Cost of sales $89,600 $106,000. Selling & administrative costs The best estimate of the total monthly fixed cost is A.$427,600 B.$528,500 C.$24,000 D.$478,050 ***PLEASE SHOW HOW to get the answer***