A graduated commission employee makes 3.5% interest on the first $50,000 in sales and 6.5% interest on all sales over $50,000. Which of the following expressions represents the employee’s total earnings on $81,500 in sales? a. (0.035)(50,000) + (0.065)(81,500) b. (0.035)(50,000) + (0.065)(31,500) c. (0.35)(50,000) + (0.65)(31,500) d. (3.5)(50,000) + (6.5)(31,500)