Project A has cash flows with a present value of $20,000 and an upfront investment of $4,000. Project B has cash flows with a present value of $9,000 and an upfront investment of $3,000. Project C has cash flows with a present value of $2,000 and an upfront investment of $2,500. What order of preference should the projects be placed in from most preferred to least preferred if profitability index is the decision criteria?