A kettle receives $600\,\text{kJ}$ of electrical energy. From this energy, $45\,\text{kJ}$ is passed to the surroundings and $15\,\text{kJ}$ is used in heating the kettle casing. The energy left over is transferred to the water. What is the efficiency of the kettle?
- A$0.10$
- B$0.90$
- C$0.925$
- D$0.975$