(A)the amount of income-tax calculated on the amount of income by way of ][dividends other than dividends referred to in section 115-O] [ Substituted by Act 32 of 2003, Section 50, for " dividends" (w.e.f. 1.4.2004).][, if any, included in the total income, at the rate of twenty per cent.; [Inserted by Act 66 of 1976, Section 20 (w.e.f. 1.6.1976).]