An electric motor delivers $120\,\text{W}$ of useful mechanical output power. The motor has an efficiency of $60\%$. Which row is the correct one?
- Aelectrical power input $72\,\text{W}$, waste heat power output $48\,\text{W}$
- Belectrical power input $192\,\text{W}$, waste heat power output $72\,\text{W}$
- Celectrical power input $200\,\text{W}$, waste heat power output $72\,\text{W}$
- Delectrical power input $200\,\text{W}$, waste heat power output $80\,\text{W}$