Which of the Following Mixtures Gives a Buffer with a PH

Which of the following mixtures gives a buffer with a pH greater than 7.0? For HCNO, K_a = 2.2 * 10^-4 and for NH₃,K_b = 1.8 * 10^-5.

A) 10 mL of 0.1 M NH₃(aq) + 10 mL of 0.1 M HCl(aq)
B) 10 mL of 0.1 M HCNO(aq) + 10 mL 0f 0.1 M NaOH(aq)
C) 10 mL of 0.1 M HCNO(aq) + 5.0 mL of 0.1 M NaOH(aq)
D) 10 mL of 0.1 M NH₃(aq) + 10 ml of 0.1 M HCNO(aq)
E) 10 mL of 0.1 M NH₃(aq) + 5.0 mL of 0.1 M HCl(aq)