(c)[ in the case of any block of assets,- [ Inserted by Act 46 of 1986, Section 8 (w.e.f. 1.4.1988).](i)in respect of any previous year relevant to the assessment year commencing on the 1st day of April, 1988, the aggregate of the written down values of all the assets falling within that block of assets at the beginning of the previous year and adjusted,-(A)by the increase by the actual cost of any asset falling within that block, acquired during the previous year;(B)by the reduction of the moneys payable in respect of any asset falling within that block, which is sold or discarded or demolished or destroyed during that previous year together with the amount of the scrap value, if any, so, however, that the amount of such reduction does not exceed the written down value as so increased; and](C)[ in the case of a slump sale, decrease by the actual cost of the asset falling within that block as reduced- [ Inserted by Act 27 of 1999, Section 26 (w.e.f. 1.4.2000).]