38) What happens when the cost-driver level increases within the relevant range? A) total variable costs decrease Btotal fixed costs remain unchanged C) variable costs per unit increases D) fixed costs per unit increases b 39) The Rock Company used regression analysis to predict the annual cost of utilities. The results were 39) as follows: Utilities Cost Explained by Direct Labor Hours Constant 2,500 Standard error of Y estimate 595 R-Squared 0.8650 No. of observations 30 Degrees of freedom 28 X Coefficient 2.037 Standard error of coefficient 0.917 The variable cost per direct labor hour is A) $595 C) $2.037 B) $2,500 D) none of the above