Which weak acid would be best to use when preparing a buffer solution with a pH of 8.50?

Question

1) an acid with Ka=3.3x10^-9
2) an acid with Ka=5.0x10^-4
3) an acid with KA=6.3x10^-6
4) an acid with Ka=5.0x10^-7
5) an acid with Ka=4.0x10^-5
6) an acid with Ka=2.0x10^-10

Answer 1

why nobody reply bruh

Answer 2

I’m done for

Answer 3

pls let me sleep