Sales volume was 1,000 Units. The following costs are the total costs for 1000 units. Please estimate unit variable cost using the following information: Hint: use account classification (account analysis) method fire insurance (a lump sum amount each year) assembly workers' wages production supervisor's salary direct materials rent A. $15 per unit OB. $40 per unit OC. $25 per unit OD. $52 per unit $1,000 $15,000 $6,000 $25,000 $10,000