Which of the Following Acids (Listed with PK_a Values) and Its

Multiple Choice

Which of the following acids (listed with pK_a values) and its conjugate would be the best choice to make a buffer with a pH of 5.20?

A) HC₇H₅O₂, pK_a = 4.19
B) HF, pK_a = 3.46
C) HClO, pK_a = 7.54
D) HCN, pK_a = 9.31
E) HClO₂, pK_a = 1.96