Which is a characteristic of an instance variable in a class?

In object-oriented programming, particularly in the context of classes, instance variables are defined within a class but are tied to a specific object or instance of that class. This means that each instance of a class has its own copy of the instance variable, which allows for the storage of unique values for each object.

When an instance variable is unique to each instance, it allows each object created from the class to maintain its own state. For example, if you create multiple objects of a class that represents a Car, each Car object can have its own unique values for instance variables such as color, model, and speed. This is crucial for accurately representing and managing the properties of individual objects.

In contrast, shared characteristics or static variables would be accessed through the class itself rather than through instances of the class, and thus do not vary from one instance to another. This differentiation is fundamental to the principles of encapsulation and object-oriented design, ensuring that instances maintain their own data independently.

So, the correct understanding of instance variables as unique to each instance illustrates the core idea of how objects behave and hold data in object-oriented programming.