Assume you think a boom and a recession are equally likely to happen, a 50-50 chance of either. State of Economy Security Returns if State Occurs Probability of State of Economy Security L Security U Recession 0.50 -20% 30% Boom 0.50 70% 10% Based on the above information, what is a standard deviation for Security U? Select one: a. 25% b. 45% c. 20% d. 10%