What consists of methods to interact with an instance?

The correct answer is class interface because it defines the methods and properties that instances of a class will use to interact with each other and with the external environment. A class interface essentially serves as a contract that specifies what functionalities are available to users of the class. This can include method signatures and property definitions, indicating how an individual instance of the class can be manipulated and interacted with.

In contrast, class instantiation refers to the process of creating an individual instance (or object) from a class, while class attributes are variables associated with a class that hold data relevant to the class's instances. A class object represents a specific instance of a class, which itself does not inherently include the methods for interaction—it is the class interface that outlines how those objects can be used effectively.