The Invoice Service in an Accounting Firm Is Heavily Reused

Multiple Choice

The Invoice service in an accounting firm is heavily reused by different service compositions. The owners of the service decide to protect its integrity by disallowing access to any part of its underlying implementation and further want to avoid the risk of having this service create a single point of failure. Which two patterns should they apply in order to accomplish this goal?

A) Contract Centralization, Decoupled Contract
B) Domain Inventory, Redundant Implementation
C) Data Model Transformation, Service Data Replication
D) Contract Centralization, Redundant Implementation