The mediation proceedings under this Act shall be deemed to terminate—
(a) on the date of signing and authentication of the mediated settlement agreement; or
(b) on the date of the written declaration of the mediator, after consultation with the parties or otherwise, to the effect that further efforts at mediation are no longer justified; or
(c) on the date of the communication by a party or parties in writing, addressed to the mediator and the other parties to the effect that the party wishes to opt out of mediation;
(d) on the expiry of time limit under section 18.