For the purposes of this Act –
(a) A postal item shall be deemed to be in a state of circulation by the post from the time it is delivered to the post office until the time the item is delivered to the addressee or returned to the sender or action is taken under section 7.
(b) Any type of postal item shall be deemed to have been delivered to the post office after it has been delivered to the person authorized to do so at the post office.
(c) Any postal item shall be deemed to have been delivered to the addressee after it has been delivered to the addressee or the heir authorized by the addressee to deliver the item.