(1) Subject to subsection (3), sections 37 and 89(2), Parts 6, 10 and 11, the Circuit Court shall have exclusive jurisdiction under this Act and the performance of the functions of that court conferred by this section shall be within the jurisdiction of the circuit of the Circuit Court and such jurisdiction shall be exercised by the circuit of the Circuit Court in which the following persons are residing or carrying on business at the time the application or appeal concerned is made, or have resided at any time during the period of 3 years immediately prior to the making of the application or the lodging of the appeal concerned:

(a) the relevant person (including a ward) the subject of an application under this Act;

(b) in the case of proceedings under section 15, the decision-making assistant appointer, whose decision-making assistant or decision-making assistance agreement is the subject of an application or appeal under that section;

(c) in the case of proceedings under Part 4, the co-decision-maker appointer, whose co-decision-maker or co-decision-making agreement is the subject of an application or appeal under that Part;