The arrangement shown uses two cells of electromotive force (e.m.f.) $3.0\,\text{V}$ and $1.2\,\text{V}$, with internal resistance taken as negligible, connected to resistors with resistance $9.0\,\Omega$ and $18\,\Omega$. What is the current $I$ in the $9.0\,\Omega$ resistor?
- A$0.10\,\text{A}$
- B$0.20\,\text{A}$
- C$0.30\,\text{A}$
- D$0.47\,\text{A}$