The question is really asking which of these four bodies has a specific statutory licence to depart from strict evidentiary rules, so each option can be checked for whether such a licence exists.
Because this specific statutory exemption exists only for arbitration and not for the three other statutory tribunals listed, the arbitral tribunal is the forum where the Bharatiya Sakshya Adhiniyam does not strictly apply.
Grouping the four options into statutory tribunals on one side and arbitration on the other makes the contrast easy to see, since three of the options share a common feature that the fourth deliberately lacks.
Because the three statutory tribunals sit on the side of forums that generally observe evidentiary principles, while arbitration alone carries an express exemption from those strict rules, the arbitral tribunal is the correct forum where the Adhiniyam does not strictly apply.
Therefore, the correct answer is Arbitral Tribunal.