The mixture which can act like a basic buffer is 

100 ml of 0.1M HCl + 100 ml  of 0.05M ${\text{NH}}_4\text{OH}$

100 ml of 0.1M NaOH + 100ml of 0.1M ${\text{CH}}_{\text{3}}\text{COOH}$

200 ml of 0.1 M NaOH + 100 ml of 0.1M ${\text{CH}}_{\text{3}}\text{COOH}$

200 ml of 0.05 M  HCl  + 100 ml of 0.2M ${\text{NH}}_4\text{OH}$