An organization has outsourced the development of a core application. However, the organization plans to bring the support and future maintenance of the application back in-house. Which of the following findings should be the IS auditor's GREATEST concern?

A. A training plan for business users has not been developed.
B. The cost of outsourcing is lower than in-house development.
C. The vendor development team is located overseas.
D. The data model is not dearly documented.