What is the payback period for Tangshan Mining company's new project if its initial after tax cost is $5,000,000 and it is expected to provide after-tax operating cash inflows of $1,800,000 in year 1, $1,900,000 in year 2, $700,000 in year 3 and $1,800,000 in year 4?
a. 3.33 years.
b. 4.33 years.
c. 2.33 years.
d. None of the above