The following situation occurs:
The two objects are brought close to each other (but they do not touch). Object B must be negatively charged: in this case, for induction, the positive charges on object A migrate towards the side of the object closer to object B, while the negative charges migrate to the other side. Then, object A must be connected to the ground, so that the negative charges migrate to the ground: therefore, an excess of positive charges remain on object A, which is now positively charged.