What do we mean by the word "composition"? AIf B has A, we can note A as an interface to loosen the coupling between B and A. 如果B has A,将A声明为接口类型可以降低AB之间的耦合度。 BIf B has a A, B knows everything of A. 如果B has A,B知道A的一切。 CIf A is part of B, we say B has a A, and this is the composition relationship. 如果A是B的一部分非，我们就说B has A，这就是组合关系。 DComposition is a kind of "has a" relationship. Composition这种关系可以描述为“has a”

The correct answer is D. Composition is a kind of "has a" relationship between two classes in object-oriented programming. It describes a relationship between two classes where one class (the composite) contains an object of another class (the component) as a member variable. The composite class "has a" component object, which it may use to perform some functionality. The composite class is responsible for managing the lifecycle of the component object. This relationship is commonly used to build complex objects by combining simpler objects.