A company is using the high-low method and has determined the following production for the months of January, February, March, and April of 6,000, 5,000, 5,550, and 2,000, respectively. During the same months, the costs were $500,000, 400,000, 425,000, and 200,000. The fixed costs are:
a. 150,000
b. 450,000
c. 50,000
d. 75,000