Assume that security returns are generated by the single$-$index model,

$R_i=a_i+{}_i{R}_M+e_i$

where $R_i$ is the excess return for security i and $R_M$ is the market's excess return. The risk$-$free rate is $2\%.$ Suppose also that there are three securities $A,B,$ and $C,$ characterized by the following data:

$\backslash$table$[[$Security$,B_i,E(R_i),(e_i)$