You Have Solutions of 0 $\times$ 10^-4)

You have solutions of 0.200 M HNO₂ and 0.200 M KNO₂ (K_a for HNO₂ = 4.00 $\times$ 10^-4) .A buffer of pH 3.000 is needed.What volumes of HNO₂ and KNO₂ are required to make 1 liter of buffered solution?

A) 500 mL of each
B) 286 mL HNO₂;714 mL KNO₂
C) 413 mL HNO₂;587 mL KNO₂
D) 714 mL HNO₂;286 mL KNO₂
E) 587 mL HNO₂;413 mL KNO₂