If two identical conducting spheres are in contact, any excess charge will be evenly distributed between the two. Three identical metal spheres are labeled $A, B,$ and $C .$ Initially, $A$ has charge $q, \mathrm{B}$ has charge $-q / 2,$ and $\mathrm{C}$ is uncharged. What is the final charge on each sphere if $\mathrm{C}$ is touched to $\mathrm{B},$ removed, and then touched to A?