3. Prior to seeking or relying upon a health care decision by a surrogate for a patient under this article, if the attending physician or attending nurse practitioner has reason to believe that the patient has a history of receiving services for mental retardation or a developmental disability; it reasonably appears to the attending physician or attending nurse practitioner that the patient has mental retardation or a developmental disability; or the attending physician or attending nurse practitioner has reason to believe that the patient has been transferred from a mental hygiene facility operated or licensed by the office of mental health, then such physician or nurse practitioner shall make reasonable efforts to determine whether paragraphs (a), (b) or (c) of this subdivision are applicable:

1. (a) If the patient has a guardian appointed by a court pursuant to article seventeen-A of the surrogate's court procedure act, health care decisions for the patient shall be governed by section seventeen hundred fifty-b of the surrogate's court procedure act and not by this article.
2. (b) If a patient does not have a guardian appointed by a court pursuant to article seventeen-A of the surrogate's court procedure act but falls within the class of persons described in paragraph (a) of subdivision one of section seventeen hundred fifty-b of such act, decisions to withdraw or withhold life-sustaining treatment for the patient shall be governed by section seventeen hundred fifty-b of the surrogate's court procedure act and not by this article.
3. (c) If a health care decision for a patient cannot be made under paragraphs (a) or (b) of this subdivision, but consent for the decision may be provided pursuant to the mental hygiene law or regulations of the office of mental health or the office for people with developmental disabilities, then the decision shall be governed by such statute or regulations and not by this article.