A rubber band is pulled out and then allowed to return to its original length. The diagram gives the force-extension graph for this sequence. When the force is increased, the graph goes along OPQ to extension $e$. When the force is decreased, the graph goes along QRO to come back to zero extension. The area marked $X$ lies between the curves OPQ and QRO. The area marked $Y$ is enclosed by the curve QRO and the horizontal axis. Which statement about the process is correct?
- AArea $X$ is the energy which heats the band as it is stretched to extension $e$.
- B$(\text{Area } X + \text{area } Y)$ is the minimum energy required to stretch the band to extension $e$.
- CArea $X$ is the elastic potential energy stored in the band when it is stretched to extension $e$.
- D$(\text{Area } Y - \text{area } X)$ is the net work done on the band during the process.