Which of the following statements is incorrect in the light of provisions of Hindu Marriage Act, 1955?

Section 22 of the Hindu Marriage Act makes every proceeding under the Act a proceeding in camera, and this is mandatory rather than dependent on a party's request; so the statement "Proceedings may be held in camera on the request of the party" is the incorrect one. Section 21C makes documents admissible despite lack of stamping or registration, section 28(3) bars an appeal on the subject of costs only, and section 28(4) allows ninety days for an appeal.