You are designing a testing methodology for an ASP.NET MVC 2 Web application. The
application has a rich domain model that represents the logic and the data of the business.
A facade over the domain model provides a simplified API that is used by the controllers. A
data access layer beneath the domain model is used by the domain model to handle data
storage and retrieval. You have the following requirements: Centralize business rules.
Directly validate the accuracy of the business rules. You need to design tests against the
appropriate layer to meet the requirements. Which layer should you recommend?

A.
the domain model facade

B.
the data access layer

C.
the controllers

D.
the domain model