user: Question: What is the torque of the xDrive20d model, which has a power of PS (kW; hp)@4000?
Columns: ['Model', 'Years', 'Engine code', 'Power', 'Torque']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['sDrive16d', '2012-', 'N47D20', 'PS (kW; hp)@4000', 'N·m (lb·ft)@1750-3000']
SQL:

assistant: SELECT "Torque" FROM "Table" WHERE "Power" = 'PS (kW; hp)@4000' AND "Model" = 'xDrive20d';