Which type of relationship between classes in OOP is best represented when one class is a part of another class but can exist independently?

Aggregation is a type of association that represents a "whole-part" relationship between two classes. The key characteristic is that the part (child object) can exist independently of the whole (parent object). For instance, in a Team class and Player class, a Player can exist without being associated with a Team . Aggregation is implemented by using references, where one class has an attribute referencing another class. This design principle promotes flexibility and modularity. Aggregation is often represented with a hollow diamond in UML diagrams. Why Other Options Are Wrong Option B : "Inheritance" Inheritance represents an "is-a" relationship, not a "whole-part" relationship. It is used to share functionality between classes, not to model part-whole dependencies. Option C : "Composition" Composition is similar to aggregation but with a crucial difference: the part cannot exist independently of the whole. For example, a Car and its Engine share a composition relationship because an engine has no meaning outside the car. Option D : "Association" Association is a broader concept that describes any relationship between classes. Aggregation is a specific type of association. Option E : "Polymorphism" Polymorphism is unrelated to class relationships and focuses on method behavior.