The owner of a number of gas stations is considering installing coffee machines in his gas stations. It will cost $270,000 to install the coffee machines, and they are expected to boost cash flows by $120, 536 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) 1.89% B) 7.55% C) 3.78% D) 9.44%