Shine Corporation has the following information for last year: Budget Actual Sales in units 18,300 17,000 Sales Revenue $ 183,000 $ 178,500 Less: Variable Expenses 109,800 100,300 Contribution Margin $ 73,200 $ 78,200 Less: Fixed Expenses 44,000 51,400 Operating Income $ 29,200 $ 26,800 With respect to Shines's sales revenue, it's sales-volume variance is: O $13,000 favorable O $5,000 favorable O $4,500 unfavorable O $13,000 unfavorable