What Combination of Substances Will Give a Buffered Solution That $\times$

Multiple Choice

What combination of substances will give a buffered solution that has a pH of 5.05? (Assume each pair of substances is dissolved in 5.0 L of water. ) (K_b for NH₃ = 1.8 $\times$ 10^-5;K_b for C₅H₅N = 1.7 $\times$ 10^-9)

A) 1.0 mole NH₃ and 1.5 mole NH₄Cl
B) 1.5 mole NH₃ and 1.0 mole NH₄Cl
C) 1.0 mole C₅H₅N and 1.5 mole C₅H₅NHCl
D) 1.5 mole C₅H₅N and 1.0 mole C₅H₅NHCl
E) none of these