When two uncharged dry objects A and B are rubbed against each other, which of the following is possible to happen?

When two uncharged dry objects are rubbed against each other, both of them acquire equal and opposite charges. 

This is because while rubbing, electrons move from one surface to the other. The surface that loses electrons become positively charged. And the other object which gains electrons becomes negatively charged. In this process, charges are conserved.