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

### Instruction:
What is the total amount of freight produced of u28c?

### Inputs:
table_name: table, columns: ['PRR Class', 'Builder’s Model', 'Build date', 'Total produced', 'Wheel arrangement', 'Service', 'Power output']

### Response:
SELECT Total produced FROM table WHERE Service = freight AND Builder’s Model = u28c