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

### Instruction:
What is the D48 when the D 50 O is d 31?

### Inputs:
table_name: table, columns: ['D 41 √', 'D 42 √', 'D 43 √', 'D 44 √', 'D 45 √', 'D 46 √', 'D 47 √', 'D 48 √', 'D 49 √', 'D 50 O']

### Response:
SELECT D 48 √ FROM table WHERE D 50 O = d 31