What is required for an implementation of IT Service Management to be successful?

A.
A top-down approach whereby the management of the organization strongly and visibly
enforces the implementation
B.
Buy-in specifically from the levels in the organization which will be operationally involved in IT
Service Management activities
C.
The appointment of a specialist department responsible for the development of the process
structures
D.
The involvement and commitment of personnel at all levels in the organization from
operational staff to top management