Which of the following additional properties is supposed to be satisfied by a group (G, *) to be an abelian group?

Explanation

By definition, a group (G, *) already satisfies closure, associativity, the existence of an identity element, and the existence of inverses for every element. An abelian group is simply a group that additionally satisfies the commutative property, i.e., a*b = b*a for all a, b in G. Identity, inverse and associativity are already required for any structure to qualify as a group in the first place.