Which data type contains properties and methods?

The correct choice identifies an object as a data type that encapsulates properties and methods. In programming, particularly in languages like JavaScript and Python, an object is a complex data type that can hold collections of data and more complex entities.

Objects are defined as instances of classes or can simply be created as data structures. They enable developers to represent real-world entities by allowing multiple attributes (properties) and functions (methods) associated with these attributes. For example, a car object might have properties such as color and model, and methods like start() or stop() that define its behavior.

This capability of grouping data and functionality together makes objects fundamental for organizing code, implementing object-oriented programming principles, and facilitating reusable code structures.

The other data types—null, function, and string—do not serve the same purpose. Null represents the absence of any value, while a function is a block of code designed to perform a task but does not encapsulate data in the way an object does. Lastly, a string is a data type that represents a sequence of characters, lacking the ability to hold methods or properties associated with complex structures.