a)  Executive Fruit is considering an investment in geothermal power production; then it should choose a discount rate which reflects the risk of the project. Therefore, Executive Fruit cannot select a discount rate of its own. No, It should not discount project cash flows at 12.3%.

b) WACC of Geothermal would reflect the risk of this project better. So, 11.4% would be a better discount rate for this investment.