(a) The principal place of administration of the trust is the usual place where the day-to-day activity of the trust is carried on by the trustee or its representative who is primarily responsible for the administration of the trust.
(b) If the principal place of administration of the trust cannot be determined under subdivision (a), it shall be determined as follows:
(1) If the trust has a single trustee, the principal place of administration of the trust is the trustee’s residence or usual place of business.
(2) If the trust has more than one trustee, the principal place of administration of the trust is the residence or usual place of business of any of the cotrustees as agreed upon by them or, if not, the residence or usual place of business of any of the cotrustees.