Which principle of OOP helps to limit the scope of variables?

The principle of encapsulation is fundamental in object-oriented programming as it helps to limit the scope of variables by bundling the data (variables) together with the methods (functions) that operate on them within an object. This means that the internal state of an object is hidden from the outside world, allowing for the protection of its data.

By doing this, encapsulation restricts direct access to some of an object's components, which can prevent unintended interference and misuse of the data. As a result, encapsulated variables (often termed as 'private' variables) can only be accessed or modified through public methods (getters and setters) provided by the class, ensuring that any interaction with the object's state is controlled. This promotes integrity and reduces the chances of accidental changes that could compromise the object's state or lead to errors.

In contrast, other principles like polymorphism, inheritance, and abstraction address different aspects of design in OOP, such as method behavior across different classes, the relationship between classes, and simplifying complex systems, but do not specifically focus on limiting the variable scope in the manner encapsulation does.