S. 23 : Income from house property-Annual value-Unsold units in commercial complex held as stock-in-trade-Notional value cannot be assessed-Reassessment beyond four years held to be not valid-Reassessment with in four years and assessment completed under section 143(1)-Reassessment is valid. [S. 22, 23(5), 24(a), 143(1)(143(3), 147, 148]