What is a class in programming?

A class in programming, particularly in the context of object-oriented programming (OOP), serves as a blueprint for creating objects. This blueprint defines the properties (attributes) and behaviors (methods) that the objects created from it will have. When a class is instantiated, it produces an object that inherits the structure and behavior defined by the class.

This concept emphasizes encapsulation, where data and functionality are bundled together. The class encapsulates the attributes and methods that govern how instances of that class behave, making it fundamental to OOP practices such as inheritance and polymorphism.

While the other options describe different concepts within programming, they do not capture the comprehensive role of a class. A class is not just a single instance since it can produce many instances (objects). It also isn't a standalone block of code meant for execution or a type of function, as a class encompasses multiple objects and methods, effectively acting as a template rather than a single executable entity. This foundational understanding highlights the significance of classes in developing robust and reusable code in OOP.