Calculate the payback period of project S considering the following estimated data: Initial cost at time 0=$1,000. After-tax, end of year cash inflows are as follows: first year: $500; second year: $400; third year. $300; fourth year: $100. The risk-adjusted cost of capital (or WACC) is 10%. Select one: a. 3.30 b. 2.80 C. 2.33 d. 2.70