The mass percentage of an element in a compound is found by dividing the total mass of that element in one mole by the molar mass of the compound and multiplying by one hundred. Here each molecule contains exactly one nitrogen atom, whose atomic mass is 14 g mol^-1, and the molar mass of the amine is given as 73 g mol^-1. Therefore the nitrogen percentage equals (14/73) × 100, which is approximately 19.2%. The option 14.0% mistakenly reports the atomic mass of nitrogen as if it were a percentage and is dimensionally meaningless here. The option 23.3% would correspond to a smaller molar mass of about 60 g mol^-1, not 73, so it does not match the data. The option 9.6% would require two nitrogen-free dilution or a much larger molar mass and is inconsistent with a single nitrogen in a 73 g mol^-1 molecule. This type of elemental composition calculation underlies Duma's and Kjeldahl's nitrogen estimation methods discussed in NCERT. As a plausibility check, a molar mass of 73 with one nitrogen fits a C4H11N amine such as butylamine, and 14 of 73 being just under one-fifth confirms the 19.2% result.