Which statements may an interface contain?

In the context of ABAP programming, an interface is designed to define a contract that classes can implement. Within an interface, the primary function is to declare methods that must be implemented by any class that adopts the interface. Therefore, the statement that an interface may contain methods is fundamentally correct.

Interfaces primarily focus on defining behavior; they lay out a set of method signatures that implementing classes are required to provide. This allows for polymorphism, enabling different classes to implement the same methods defined in the interface in various ways, which is crucial for achieving flexible and scalable software design.

While other elements such as class definitions, types, and public sections play significant roles in ABAP, they do not pertain to the structure or content of an interface specifically. Class definitions are utilized when creating a class and include encapsulated data and methods, types define data structures, and the public section pertains to visibility within ABAP objects, but none of these are part of what is contained within the interface itself. Thus, focusing on methods clarifies why it is the correct answer in the context of a statement about the contents of an interface in ABAP.