In our notes we learned about NPV profile graphs, which in those notes plot a. The NPV on the vertical axis and the inflation rate on the horizontal axis b. The NPV on the vertical axis and the payback period on the horizontal axis c. The NPV on the vertical axis and the cost of capital on the horizontal axis d. The return on investment on the vertical axis and the NPV on the horizontal axis e. The cost of capital on the vertical axis and NPV on the horizontal axis answer and why