You have three pairs of spheres. Pair A consists of two conducting spheres, pair B of two nonconducting spheres, and pair \(\mathrm{C}\) of one nonconducting sphere and one conducting sphere. If the same charge \(q\) is added to all spheres uniformly and in each pair the two spheres are separated by the same distance \(d\), rate the magnitude of the electric force between each pair's spheres when \(q\) is \((a)\) positive on both spheres, \((b)\) negative on both, and \((c)\) positive on one sphere in the pair and negative on the other.