You are an enterprise application developer. You create a Web service that wraps a business component to expose it through the Web. The business component contains two classes, the Utility class and the Facade class. The Utility class has private methods and internal methods. The Facade class has public methods. The Web service component has a Web service class that is named Services. The Services class performs security verification before the functions in the business component are called. The Services class relies on a class that is named Security in the Web service to implement the security verification. You have completed unit testing both components. You need to choose the class for which to write test cases for integration testing.
Which class should you choose?

A.
Utility

B.
Facade

C.
Services

D.
Security