Which of the following solutions will be the best buffer at a pH of 9.26? (Ka for HC₂H₃O₂ is 1.8 × 10⁻⁵, Kb for NH₃ is 1.8 × 10⁻⁵).
a) 0.10 M HC₂H₃O₂ and 0.10 M Na C₂H₃O₂
b) 5.0 M HC₂H₃O₂ and 5.0 M Na C₂H₃O₂
c) 0.10 M NH₃ and 0.10 M NH₄Cl
d) 5.0 M NH₃ and 5.0 M NH₄Cl
e) 5.0 M HC₂H₃O₂ and 5.0 M NH₃