Returns for the Dayton Company over the last 3 years are shown below. What's the standard deviation of the firm's returns? (Hint: This is a sample, not a complete population, so the sample standard deviation formula should be used.) Do not round your intermediate calculations. Year Return 2013 21.00% 2012 -12.50% 2011 35.00% O a. 23.43 O b. 24.4196 O c. 27.0996 O d. 30.0296 O e. 18.79%