Final answer:
The primary basis for ongoing case management intervention is the Case plan, which is a structured outline of goals and steps tailored to the client's needs and is continuously updated.
Step-by-step explanation:
The primary basis for ongoing case management intervention is D. Case plan. A case plan is essentially a roadmap designed by case workers to help meet the client's needs and objectives. It outlines specific, measurable, attainable, relevant, and time-bound (SMART) goals and steps to achieve them. The case plan is continually reassessed and updated based on changes in circumstances or progress.
Safety assessment is important, but it's typically part of the initial stages of case management, used to ensure the immediate protection of individuals, particularly in situations involving minors or vulnerable adults. Family functioning assessment helps inform the case plan but is not the ongoing basis for intervention. Child custody can be an aspect of the case management process, but it is not the general basis for all case management interventions.