The owner of a number of gas stations is considering installing coffee machines in his gas stations. It will cost $300,000 to install the coffee machines, and they are expected to boost cash flows by $133,929 per year for their five-year working life. What must the cost of capital be if this investment has a profitability index of 1? A. 3.78% B. 7.55% C. 1.89% D. 9.44%