What does the term "encapsulation" refer to in object-oriented programming?

Encapsulation in object-oriented programming is best understood as the bundling of data with the methods that operate on that data. This concept promotes a clear separation between the internal workings of a class and the external code that interacts with it. By encapsulating data and the methods that manipulate that data, a class can control access to its internal state and protect it from unintended interference or misuse.

Encapsulation allows for data hiding; for instance, instance variables can be made private, preventing outside code from directly accessing or modifying them. Instead, public methods (often referred to as getters and setters) are provided, which dictate how this data can be accessed or changed. This leads to more robust and maintainable code, as it minimizes dependencies between different parts of the program and allows for easier updates and changes in implementation without affecting external code.

The other choices do not accurately describe encapsulation. While optimizing code execution, inheriting properties from another class, and using complex data types are relevant concepts in object-oriented programming, they do not encapsulate the core idea of combining data and methods into a single unit, which is fundamental to encapsulation.