A student adds 0.1 mol of oxalic acid and 0.1 mol of sodium dihydrogen phosphate to enough water to make 1.0 L of solution. The following equilibrium is established with the concentrations of the products greater than the concentrations of the reactants. Which of the statements about the equilibrium system is correct?

H2C2O4(aq) + H2PO4-(aq) HC2O4-(aq) + H3PO4(aq)

A) Oxalic acid is a weaker acid than phosphoric acid.

B) The hydrogen oxalate anion, HC2O4-, is a stronger base than the dihydrogen phosphate anion, H2PO4- .

C) Phosphoric acid is a weaker acid than oxalic acid.

D) The dihydrogen phosphate anion, H2PO4-, is a stronger acid than oxalic acid.

E) Water is a stronger acid than either oxalic or phosphoric acids.

can someone give me explanations why EACH one isn't or is the right answer. I'm studying for a test but want to understand the concept. the answer is C