calculate the discounted payback period for 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 (WACC) is 10%

A. 2.95

B. 4.2

C. 3.1

D. 3.78