The diagram represents a circuit made up of a power supply, a lamp and a motor. Three ammeters are used to measure the current at different positions in the circuit. The ammeter readings are $I_1$, $I_2$ and $I_3$. Which statement about the ammeter readings is correct?
- AAll three readings are the same.
- B$I_1$ is greater than $I_2$ and is greater than $I_3$.
- C$I_2$ is greater than $I_1$ and is greater than $I_3$.
- D$I_3$ is greater than $I_1$ and is greater than $I_2$.