It is presumed that there is legal subrogation:
(1) When a creditor pays another creditor who is preferred, even without the debtor's knowledge;
(2) When a third person, not interested in the obligation, pays with the express or tacit approval of the debtor;
(3) When, even without the knowledge of the debtor, a person interested in the fulfillment of the obligation pays, without prejudice to the effects of confusion as to the latter's share. (1210a)