Which of the Following Mixtures Would Make a Buffer of PH

Multiple Choice

Which of the following mixtures would make a buffer of pH = 4.74? (pK_a of acetic acid is 4.74)

A) 100 mL of 0.10 M HCl and 100 mL of 0.10 M NaC₂H₃O₂
B) 100 mL of 0.10 M HCl and 100 mL of 0.10 M HC₂H₃O₂
C) 50 mL of 0.10 M HC₂H₃O₂ and 100 mL of 0.10 M NaC₂H₃O₂
D) 100 mL of 0.10 M NaOH and 100 mL of 0.10 M NaC₂H₃O₂
E) 50 mL of 0.10 M NaOH and 100 mL of 0.10 M HC₂H₃O₂