Within what period must a prescribed class of unlisted companies file a copy with the Registrar after the completion of the relevant period?

Section 129A. Periodical financial results: The Central Government may, require such class or classes of unlisted companies, as may be prescribed,— (a) to prepare the financial results of the company on such periodical basis and in such form as may be prescribed; (b) to obtain approval of the Board of Directors and complete audit or limited review of such periodical financial results in such manner as may be prescribed; and (c) file a copy with the Registrar within a period of thirty days of completion of the relevant period with such fees as may be prescribed