The diagram illustrates a simple circuit. Which of the following statements is correct?
- AWhen switch $S$ is closed, the electromotive force (e.m.f.) of the battery falls because work is done against the internal resistance of the battery.
- BWhen switch $S$ is closed, the e.m.f. of the battery falls because work is done against the resistance $R$.
- CWhen switch $S$ is closed, the potential difference across the battery falls because work is done against the internal resistance of the battery.
- DWhen switch $S$ is closed, the potential difference across the battery falls because work is done against the resistance $R$.