What volumes of 0.200 M `HNO_2` and 0.200 M `NaNO_2` are required to make 500 mL of a buffer solution with pH =3.00 ? [`K_a` for `HNO_2=4.00xx10^(-4)`]
A. 250 mL of each
B. 143 mL of `HNO_2` and 357 mL of `NaNO_2`
C. 200 mL of `HNO_2` and 300 mL of `NaNO_2`
D. 357 mL of `HNO_2` and 143 mL of `NaNO_2`