Based on analyzing the last 100 years of returns, stock returns have been more risky than bonds because they had Choose the best answer. O a higher standard deviation of returns O higher returns O more inflation risk O none of the above What is the approximate standard deviation of returns if over the past four years an investment returned 4.0%, -12.0%, -12% and 25.0%? O 9.26% O 10.26% O 15.18% O 16.01% Sunk costs should not be included as part of project cash flows. O True False