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

### Instruction:
List all GT4 Cup winners played on the Spa-Francorchamps Report.

### Inputs:
table_name: table, columns: ['Event', 'Circuit', 'GT3 Pro Cup Winner', 'GT3 Pro / Am Cup Winner', 'GT3 Citation Cup Winner', 'GT4 Cup Winner']

### Response:
SELECT GT4 Cup Winner FROM table WHERE Circuit = Spa-Francorchamps Report