Returns for the Alcoff 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.)

Year	Return
2010	21.00%
2009	12.50%
2008	38.40%

a. 25.78%

b. 25.87%

c. 25.81%

d. 25.84%

e. 25.90%