Which Solution Below Would Be the Best Choice for Preparing

Multiple Choice

Which solution below would be the best choice for preparing a buffer with a pH =5.0?

A) formic acid and sodium formate, K_a = 1.8 * 10^-4
B) acetic acid and sodium acetate, K_a =1.8*10^-5
C) hypochlorous acid and sodium hypochlorite, K_a =3.5*10^-8
D) boric acid and sodium borate, K_a = 5.8 *10^-10
E) All of these solutions would be equally good choices for making this buffer.