Which of the following options is used to combine objects so that they are considered as a single unit?

In object-oriented programming, the concept of combining objects so that they are treated as a single unit is often referred to as composition. This approach involves creating a new class that consists of one or more objects from other classes, allowing for a more modular design.

When using composition, each object maintains its own identity and state, but through their relationships, they can function together seamlessly. This contrasts with inheritance, where a new class derives behavior from a parent class.

In summary, composition is a design principle that promotes code reusability and flexibility by allowing objects to be combined to create complex data structures or functionalities while keeping the individual components manageable and understandable.