Which of the following acids (listed with Ka values) and their conjugate base should be used to form a buffer with a pH of 2.34?
A) C6H5OH, Ka = 1.3 × 10⁻¹⁰
B) HCN, Ka = 4.9 × 10⁻¹⁰
C) HN3, Ka = 2.5 × 10⁻⁵
D) HClO2, Ka = 1.1 × 10⁻²
E) HIO, Ka = 2.3 × 10⁻¹⁰