What is the standard deviation of the return of the following project?

Event	Probability of event occurring	Return on project (%)	Expected return (%)
Booming economy	0.2	35	25
Growing economy	0.6	10	10
Declining economy	0.2	5	5

Select one:

a. 15.34%

b. 10.68%

c. 5.22%

d. 25.10%