Which statement is correct? Statement A: The middle layer of the three-layer architecture consists of both the conceptual data model and the logical data model. The logical data model is physically implemented in the internal layer. Statement B: The top level of the three-layer architecture is the external layer. Views for one or more applications always offer a window on the complete logical model.

a. Only sentence A is right.

b. Only sentence B is right.

c. Sentences A and B are right.

d. Neither A nor B is right.