Object A has a charge of –1 Coulomb. According to Coulomb's law, opposite charges attract each other, and like charges repel each other. The charge that would be most strongly attracted to object A would be the one with the largest positive charge.
In the options provided, the positive charges are +2 C and +1 C. Of these two, +2 C is the stronger positive charge.
Therefore, the object that would be most strongly attracted by object A (–1 C) is +2 C.