buffers and titrations. Please Help!

Which of the following aqueous solutions makes a buffer?

0.1 M HCl + 0.2 M CaCl₂
0.1 M HCl + 0.2 M NH₃
0.1 M CH₃COOH + 0.2 M NaOH
0.1 M CH₃COONa + 0.2 M NaOH
0.25 M HCl + 0.2 M NH₃