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

### Instruction:
What is the highest quantity of the b ix k.b.sts.b.?

### Inputs:
table_name: table, columns: ['Class', 'Quantity', 'Type', 'Delivered', 'K.B.Sts.B. Class', 'Retired']

### Response:
SELECT MAX Quantity FROM table WHERE K.B.Sts.B. Class = b ix