which shows the conjugate bases listed by increasing strength?

Question

Given the following acids and Ka values:

HClO4	HOAc	HCN	HF
1 × 107	1.76 × 10–5	4.93 × 10–10	3.53 × 10–4

Which shows the conjugate bases listed by increasing strength? 

a) CN^–, F^–, OAc^–, ClO4 – 

b) CN^–, OAc–, F^–, ClO₄ ^– 

c) CN^–, ClO₄ ^–, F^–, OAc^–

d) ClO₄ ^–, OAc^–, CN^–, F^– 

e) ClO₄ ^–, F^–, OAc^–, CN^– 

Answer 1

e) ClO₄ ^–, F^–, OAc^–, CN^–