Under a modified wage plan, Jim Phillips works an eight-hour day and earns $.50 for each finished unit he produces in excess of 200 units. However, he is guaranteed $12.50 per hour as a minimum wage. His production this week was as follows: Monday Tuesday Wednesday Thursday Friday 220 units 180 units 200 units 200 units 190 units How much was the make-up guarantee paid to Jim this week? a. $10 b. $5 c. $12.50 d. $15