Returns for the Alcoff Company over the last 3 years are shown below. What's the standard deviation the firm's returns? (Hint: This is a sample, not a complete population, so the sample standard deviatic formula should be used.) Year Return 2010 21.00% 2009 -12.50% 2008 36.60% Select the correct answer. a. 24.93% b. 25.09% C. 24.97% O d. 25.01% O e. 25.05%