(b)where such loss or unabsorbed depreciation is not directly relatable to the undertakings transferred to the resulting company, be apportioned between the demerged company and the resulting company in the same proportion in which the assets of the undertakings have been retained by the demerged company and transferred to the resulting company, and be allowed to be carried forward and set off in the hands of the demerged company or the resulting company, as the case may be.