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

### Instruction:
Which Callsign has an IATA of tr?

### Inputs:
table_name: table, columns: ['Airline', 'IATA', 'ICAO', 'Callsign', 'Commenced operations']

### Response:
SELECT Callsign FROM table WHERE IATA = tr