How does encapsulation contribute to data integrity in a class?

Encapsulation plays a crucial role in maintaining data integrity within a class by restricting unauthorized access and modification. When a class uses encapsulation, it typically makes its internal data members private or protected, which prevents external code from directly accessing or altering these internal states. Instead, access to these members is facilitated through public methods (often referred to as getters and setters), which can include validation logic to ensure that any data modifications adhere to certain rules.

This controlled access ensures that the class maintains a valid state and prevents unintended interference from external entities, thereby preserving the integrity of the data. For example, if a class represents a bank account, its balance should only be modified through specific methods that enforce rules, such as preventing a negative balance. This encapsulation design protects the internal workings of the class, enabling it to manage its state reliably and safely.

The other choices do not contribute to data integrity. Allowing complete access to all internal states or exposing all methods publicly can open up the class to erroneous changes and states, while forcing all data to be static is unrelated to the concept of encapsulation and doesn’t inherently promote data integrity.