In a Volumetric Analysis Experiment,a Solution of Sodium Oxalate (Na₂C₂O₄)in

In a volumetric analysis experiment,a solution of sodium oxalate (Na₂C₂O₄) in acidic solution is titrated with a solution of potassium permanganate (KMnO₄) according to the following balanced chemical equation:
2KMnO₄(aq) + 8H₂SO₄(aq) + 5Na₂C₂O₄(aq) → 2MnSO₄(aq) + 8H₂O(l) + 10CO₂(g) + 5Na₂SO₄(aq) + K₂SO₄(aq)
It required 40.0 mL of 0.0335 M KMnO₄ to reach the endpoint.What mass of Na₂C₂O₄ was present initially?

A) 1.79 g
B) 0.0718 g
C) 11.2 g
D) 0.179 g
E) 0.448 g