Final answer:
The primary criterion for a substitute decision maker (SDM) is legal competence. This has been interpreted and defined through several key legal cases. Financial stability and medical expertise are not primary legal requirements for determining the competency of an SDM.
Step-by-step explanation:
When determining the criteria for a substitute decision maker (SDM), several factors are taken into account. The listed options A through D touch on various qualifications that may be relevant. However, from a legal perspective, the key criterion is often legal competence, as determined within various court cases. Some crucial legal cases regarding competence include:
Dusky v. United States (1960), which holds that a defendant has the right to a competency evaluation before proceeding to trial.
Rogers v. Okin (1979) which presumes the competence of a committed patient until adjudicated otherwise.
Ford v. Wainwright (1986) establishes the right to a competency evaluation before execution.
Godinez v. Moran (1993) asserts that a defendant who is competent to stand trial is automatically competent to plead guilty or waive the right to legal counsel.