Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is the On-air ID with the frequency of 105.9, and purpose of commercial?

### Inputs:
table_name: table, columns: ['Callsign', 'Area served', 'Frequency', 'Band', 'On-air ID', 'Purpose']

### Response:
SELECT On-air ID FROM table WHERE Frequency = 105.9 AND Purpose = commercial