A chemical plant with a capacity of 6,000 kg / day requires a fixed capital investment of 10 million dollars with a working capital of 25% of the total investment. In operation, it requires an annual variable production cost of $ 2,000,000 and a fixed cost of $ 700,000. If the resulting product sells for $ 3.45 / kg, how long is the payback period of the chemical plant if it is assumed that the interest rate = 10% and the plant operates 330 days / year?
A. 4.1 years
B. 5.1 years
C. 3.1 years
D. 7.1 years