Philip is the operations analyst XYZ Corporation and he wants to determine the best alternative proposed by the three functional areas of the company to improve performance. At present, the company sells 450 units per month for $70 per unit at a cost of $45 per unit. The financial cost is $7,580 per month and the income tax rate is 20%. The proposal of Marketing Department is to increase the price per unit by 15%. Finance Department wants to reduce the financial cost by 15% and Operations Department prefers to cut product cost per unit by 15%. Which proposal can provide the company the best productivity improvement option based on income after tax?