Over a period of time, fuel provides energy $X$ to a car. As the car speeds up, part of this energy is changed into kinetic energy. The remaining energy $Y$ is transferred away as thermal energy. Find the efficiency of the car.
- A$\dfrac{X}{X - Y}$
- B$\dfrac{Y}{X - Y}$
- C$\dfrac{X - Y}{X}$
- D$\dfrac{X - Y}{Y}$