Identify the mathematical equation for the radiosity $(J_i)$ of the surface $\frac{?}{?}$ that is gray and opaque, where $E_{bi}$ is the blackbody emissive power, ${}_i$ is the emissivity of the surface, and $G_i$ is the irradiation on the surface $i.$

$($A$)J_i=\frac{iEbi}{(1-i)Gi}$

$($B$)J_i=(1-{}_i){}_i{E}_{bi}{G}_i$

$($C$)J_i={}_i{E}_{bi}-(1-{}_i)G_i$

$($D$)J_i={}_i{E}_{bi}+(1-{}_i)G_i$

$A$

$B$