How many kilowatt-hours of electricity are needed to obtain 1.0×10³ kg (1 metric ton) of chromium through the electrolysis of Cr³⁺, given that this process has a 40% efficiency and the applied voltage is 5.10 V?  

• A. 3.2×10³ kWh
• B. 1.5×10⁴ kWh
• C. 2.0×10⁴ kWh
• D. 7.6×10² kWh

Answer: (C)