1.25 g of a sample of Na₂CO₃ and Na₂SO₄ is dissolved in 250 ml solution. 25 ml of this solution neutralises 20 ml of 0.1N H₂SO₄.The % of Na₂CO₃ in this sample is
A 84.80%
B 8.48%
C 15.20%
D 42.40%