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

### Instruction:
What date did the episode air that had a ranking of 17 for cable?

### Inputs:
table_name: table, columns: ['Episode no.', 'Airdate', 'Viewers', 'BBC Three weekly ranking', 'Cable rank']

### Response:
SELECT Airdate FROM table WHERE Cable rank = 17