Adjust the potentiometer to make the transistor go through all states: off/active/saturation.

What is the minimum base current for the transistor to go into 'active' and 'saturation' state? Maybe this is not a useful question; the datasheet lists only the 'Base-Emitter On Voltage' and 'Base-Emitter Saturation Voltage' with different values depending on the collector and base current.