Consider the following probability distribution for stocks A and B : The standard deviations of stocks A and B are and respectively. a. 1.5%;1.9% b. 2.5%,1.1% c. 3.2%;2.0% d. 1.5%,1.1% a. 1.596;1.996 b. 2.596:1.196 c. 3.296;2.096 d. 1.596:1.196