Calculate the variance and the standard deviation of this probability distribution.
Scenario 1: Probability 0.25, Rate of return -15%
a) Variance = 0.0025, Standard deviation = 0.05
b) Variance = 0.005625, Standard deviation = 0.075
c) Variance = 0.00625, Standard deviation = 0.05
d) Variance = 0.0025, Standard deviation = 0.025