In the Context of Outsourcing to Reduce Costs, Which of the Following

In the context of outsourcing to reduce costs, which of the following is a lesson that should be learned while outsourcing operations overseas?

A) Communicating by email and fax is enough.
B) Only problematic projects should be outsourced.
C) The regulatory requirements of an industry should be understood.
D) Problems in the beginning that slow the process should not occur and are a sign that outsourcing is a mistake.
E) All of these are correct.