Two identical metallic spheres A and B of exactly equal masses are given equal positive and negative charge respectively. Then:

The correct option is A mass of A < Mass of B
Initially, it is said in the question that both the spheres have identical mass. However, when the sphere A is given some positive charge, it has lost some electrons in the process. Whereas, Sphere B has gained electrons in order to get negatively charged.
Therefore, essentially the mass of B has increased and that of A has decreased.
Thus, Mass of A < Mass of B