Law governing validity; choice of law as to the execution of document of anatomical gift; presumption of validity.
     (a) A document of gift is valid if executed in accordance with:
         (1) this Act;
         (2) the laws of the state or country where it was
    
executed; or
        (3) the laws of the state or country where the person
    
making the anatomical gift was domiciled, had a place of residence, or was a national at the time the document of gift was executed.
    (b) If a document of gift is valid under this Section, the law of this State governs the interpretation of the document of gift.
     (c) A person may presume that a document of gift or amendment of an anatomical gift is valid unless that person knows that it was not validly executed or was revoked.