i need typed answer with explanation

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	220 units
Tuesday	180 units
Wednesday	200 units
Thursday	200 units
Friday	190 units

How much was the make-up guarantee paid to Jim this week?

a. $10

b. $5

c. $12.50

d. $15